feat: 프로젝트 활동을 만들고 고치고 지울 수 있게 한다

공개 프로젝트 화면의 "활동" 이 언제나 비어 있었다. 계약에는 목록·생성·수정이
선언돼 있었지만 구현이 없었고, `project_activity` 는 0행이었다.

이 테이블은 투영을 거치지 않는다 — 공개 조회가 `visibility = 'PUBLIC'` 조건으로
직접 읽는다. 그래서 여기서 만든 줄이 곧 그 화면이다.

`origin` 은 어댑터가 정한다. 이 경로로 들어오는 것은 언제나 `MANUAL` 이고 `AUTO` 는
게시 파이프라인의 몫이다. 클라이언트가 값을 정하게 두면 손으로 적은 줄에 `AUTO` 를
붙여 삭제 금지를 우회할 수 있다.

생성이 붙잡는 버전은 활동이 아니라 프로젝트의 것이다. 활동은 아직 없으므로 자기
버전을 가질 수 없고, 두 사람이 같은 타임라인을 동시에 고치는 것을 막으려면 붙잡을
것이 프로젝트뿐이다.

모든 쓰기에 `project_id` 조건이 붙는다. 경로가 둘을 함께 요구하므로 활동 id 만으로
수정하면 남의 프로젝트 줄을 고칠 수 있다.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XEHXspz4rv5pB5wiiSsVDu

src/adapter/inbound/web/src/main/java/dev/caskeleton/adapter/inbound/web/techlog/management/controller/ManagementProjectActivityController.java

@@ -0,0 +1,114 @@
+package dev.caskeleton.adapter.inbound.web.techlog.management.controller;
+
+import dev.caskeleton.adapter.inbound.web.auth.AuthenticatedPrincipal;
+import dev.caskeleton.adapter.inbound.web.techlog.management.ManagementPrincipals;
+import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.ExpectedVersionRequest;
+import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.ProjectActivityRequest;
+import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.ProjectActivityResponse;
+import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.UpdateProjectActivityRequest;
+import dev.caskeleton.adapter.inbound.web.techlog.management.mapper.ManagementResponseMapper;
+import dev.caskeleton.application.techlog.management.command.CreateProjectActivityCommand;
+import dev.caskeleton.application.techlog.management.command.UpdateProjectActivityCommand;
+import dev.caskeleton.application.techlog.management.service.CreateProjectActivityUseCase;
+import dev.caskeleton.application.techlog.management.service.DeleteProjectActivityUseCase;
+import dev.caskeleton.application.techlog.management.service.ListStudioProjectActivitiesUseCase;
+import dev.caskeleton.application.techlog.management.service.UpdateProjectActivityUseCase;
+import java.time.OffsetDateTime;
+import java.util.List;
+import java.util.UUID;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.core.annotation.AuthenticationPrincipal;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * 프로젝트 활동. 계약 {@code listStudioProjectActivities}/{@code createProjectActivity}/{@code
+ * updateProjectActivity}/{@code deleteProjectActivity}.
+ *
+ * <p>공개 프로젝트 화면의 "활동" 은 {@code project_activity} 를 직접 읽는다 — 투영을 거치지 않으므로 여기서 만든 줄이 곧 그 화면이다.
+ */
+@RestController
+public class ManagementProjectActivityController {
+
+  private final ListStudioProjectActivitiesUseCase listActivities;
+  private final CreateProjectActivityUseCase createActivity;
+  private final UpdateProjectActivityUseCase updateActivity;
+  private final DeleteProjectActivityUseCase deleteActivity;
+
+  public ManagementProjectActivityController(
+      ListStudioProjectActivitiesUseCase listActivities,
+      CreateProjectActivityUseCase createActivity,
+      UpdateProjectActivityUseCase updateActivity,
+      DeleteProjectActivityUseCase deleteActivity) {
+    this.listActivities = listActivities;
+    this.createActivity = createActivity;
+    this.updateActivity = updateActivity;
+    this.deleteActivity = deleteActivity;
+  }
+
+  @GetMapping("/v1/studio/projects/{id}/activities")
+  public List<ProjectActivityResponse> listStudioProjectActivities(@PathVariable("id") UUID id) {
+    return ManagementResponseMapper.projectActivities(listActivities.handle(id));
+  }
+
+  @PostMapping("/v1/studio/projects/{id}/activities")
+  @ResponseStatus(HttpStatus.CREATED)
+  public ProjectActivityResponse createProjectActivity(
+      @AuthenticationPrincipal AuthenticatedPrincipal principal,
+      @PathVariable("id") UUID id,
+      @RequestBody ProjectActivityRequest body) {
+    return ManagementResponseMapper.projectActivity(
+        createActivity.handle(
+            new CreateProjectActivityCommand(
+                id,
+                body.getExpectedProjectVersion(),
+                body.getActivityType(),
+                body.getTitle(),
+                body.getSummary(),
+                body.getVisibility() == null ? null : body.getVisibility().getValue(),
+                body.getRelatedResourceType(),
+                body.getRelatedResourceId(),
+                instant(body.getOccurredAt()),
+                ManagementPrincipals.require(principal))));
+  }
+
+  @PutMapping("/v1/studio/projects/{id}/activities/{activityId}")
+  public ProjectActivityResponse updateProjectActivity(
+      @AuthenticationPrincipal AuthenticatedPrincipal principal,
+      @PathVariable("id") UUID id,
+      @PathVariable("activityId") UUID activityId,
+      @RequestBody UpdateProjectActivityRequest body) {
+    return ManagementResponseMapper.projectActivity(
+        updateActivity.handle(
+            new UpdateProjectActivityCommand(
+                id,
+                activityId,
+                body.getExpectedVersion(),
+                body.getTitle(),
+                body.getSummary(),
+                body.getVisibility() == null ? null : body.getVisibility().getValue(),
+                instant(body.getOccurredAt()),
+                ManagementPrincipals.require(principal))));
+  }
+
+  @DeleteMapping("/v1/studio/projects/{id}/activities/{activityId}")
+  @ResponseStatus(HttpStatus.NO_CONTENT)
+  public void deleteProjectActivity(
+      @AuthenticationPrincipal AuthenticatedPrincipal principal,
+      @PathVariable("id") UUID id,
+      @PathVariable("activityId") UUID activityId,
+      @RequestBody ExpectedVersionRequest body) {
+    deleteActivity.handle(
+        id, activityId, body.getExpectedVersion(), ManagementPrincipals.require(principal));
+  }
+
+  private static java.time.Instant instant(OffsetDateTime value) {
+    return value == null ? null : value.toInstant();
+  }
+}

src/adapter/inbound/web/src/main/java/dev/caskeleton/adapter/inbound/web/techlog/management/mapper/ManagementResponseMapper.java

@@ -3,6 +3,7 @@ package dev.caskeleton.adapter.inbound.web.techlog.management.mapper;
 import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.CreateDraftResponse;
 import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.HomeFocusResponse;
 import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.PageMetadata;
+import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.ProjectActivityResponse;
 import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.ProjectEditResponse;
 import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.ProjectIndexItem;
 import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.ProjectIndexPage;
@@ -13,6 +14,7 @@ import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.ReleaseIn
 import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.ReleaseIndexPage;
 import dev.caskeleton.adapter.inbound.web.techlog.management.api.model.TopicEdit;
 import dev.caskeleton.application.techlog.management.model.HomeFocusConfigView;
+import dev.caskeleton.application.techlog.management.model.ProjectActivityView;
 import dev.caskeleton.application.techlog.management.model.ProjectEditView;
 import dev.caskeleton.application.techlog.management.model.ProjectIndexItemView;
 import dev.caskeleton.application.techlog.management.model.ReleaseEditView;
@@ -213,6 +215,29 @@ public final class ManagementResponseMapper {
         view.version());
   }
 
+  /** 프로젝트 활동 한 줄. {@code origin} 을 그대로 실어 보낸다 — 화면이 지울 수 있는 줄과 아닌 줄을 그것으로 가른다. */
+  public static ProjectActivityResponse projectActivity(ProjectActivityView view) {
+    ProjectActivityResponse response =
+        new ProjectActivityResponse(
+            view.id(),
+            view.projectId(),
+            view.activityType(),
+            view.title(),
+            view.visibility(),
+            view.origin(),
+            at(view.occurredAt()),
+            view.version());
+    response.setSummary(view.summary());
+    response.setRelatedResourceType(view.relatedResourceType());
+    response.setRelatedResourceId(view.relatedResourceId());
+    return response;
+  }
+
+  public static java.util.List<ProjectActivityResponse> projectActivities(
+      java.util.List<ProjectActivityView> views) {
+    return views.stream().map(ManagementResponseMapper::projectActivity).toList();
+  }
+
   private static String nullToEmpty(String value) {
     return value == null ? "" : value;
   }

src/adapter/outbound/persistence-jpa/src/main/java/dev/caskeleton/adapter/outbound/persistence/techlog/management/JdbcProjectActivityRepositoryAdapter.java

@@ -0,0 +1,144 @@
+package dev.caskeleton.adapter.outbound.persistence.techlog.management;
+
+import dev.caskeleton.application.techlog.management.command.CreateProjectActivityCommand;
+import dev.caskeleton.application.techlog.management.command.UpdateProjectActivityCommand;
+import dev.caskeleton.application.techlog.management.model.ProjectActivityView;
+import dev.caskeleton.application.techlog.management.port.out.ProjectActivityRepositoryPort;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.List;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.function.Supplier;
+import org.springframework.jdbc.core.simple.JdbcClient;
+import org.springframework.stereotype.Repository;
+
+/**
+ * 프로젝트 활동 편집 저장소.
+ *
+ * <p>{@code origin} 은 이 경로에서 언제나 {@code MANUAL} 이다. 이 어댑터로 들어오는 것은 작성자가 손으로 적은 줄뿐이고, {@code AUTO} 는
+ * 게시 파이프라인이 남기는 몫이다. 클라이언트가 값을 정하게 두면 손으로 적은 줄에 {@code AUTO} 를 붙여 삭제 금지를 우회할 수 있다.
+ *
+ * <p>모든 쓰기에 {@code project_id} 조건이 붙는다. 경로가 프로젝트와 활동을 함께 요구하므로, 활동 id 만으로 수정하면 남의 프로젝트에 달린 줄을 고칠 수
+ * 있다.
+ */
+@Repository
+public class JdbcProjectActivityRepositoryAdapter implements ProjectActivityRepositoryPort {
+
+  private static final String COLUMNS =
+      "id, project_id, activity_type, title, summary, visibility, origin,"
+          + " related_resource_type, related_resource_id, occurred_at, version";
+
+  private final JdbcClient jdbcClient;
+  private final Supplier<UUID> idGenerator;
+
+  public JdbcProjectActivityRepositoryAdapter(JdbcClient jdbcClient) {
+    this(jdbcClient, UUID::randomUUID);
+  }
+
+  JdbcProjectActivityRepositoryAdapter(JdbcClient jdbcClient, Supplier<UUID> idGenerator) {
+    this.jdbcClient = jdbcClient;
+    this.idGenerator = idGenerator;
+  }
+
+  private static ProjectActivityView map(ResultSet rs, int rowNum) throws SQLException {
+    return new ProjectActivityView(
+        rs.getObject("id", UUID.class),
+        rs.getObject("project_id", UUID.class),
+        rs.getString("activity_type"),
+        rs.getString("title"),
+        rs.getString("summary"),
+        rs.getString("visibility"),
+        rs.getString("origin"),
+        rs.getString("related_resource_type"),
+        rs.getObject("related_resource_id", UUID.class),
+        rs.getTimestamp("occurred_at").toInstant(),
+        rs.getLong("version"));
+  }
+
+  @Override
+  public List<ProjectActivityView> listByProject(UUID projectId) {
+    return jdbcClient
+        .sql(
+            "SELECT "
+                + COLUMNS
+                + " FROM project_activity WHERE project_id = :projectId"
+                + " ORDER BY occurred_at DESC, id DESC")
+        .param("projectId", projectId)
+        .query(JdbcProjectActivityRepositoryAdapter::map)
+        .list();
+  }
+
+  @Override
+  public Optional<ProjectActivityView> find(UUID projectId, UUID activityId) {
+    return jdbcClient
+        .sql(
+            "SELECT "
+                + COLUMNS
+                + " FROM project_activity"
+                + " WHERE project_id = :projectId AND id = :id")
+        .param("projectId", projectId)
+        .param("id", activityId)
+        .query(JdbcProjectActivityRepositoryAdapter::map)
+        .optional();
+  }
+
+  @Override
+  public ProjectActivityView create(CreateProjectActivityCommand command) {
+    UUID id = idGenerator.get();
+    jdbcClient
+        .sql(
+            "INSERT INTO project_activity (id, project_id, activity_type, title, summary,"
+                + " visibility, origin, related_resource_type, related_resource_id, occurred_at,"
+                + " created_by, updated_by)"
+                + " VALUES (:id, :projectId, :type, :title, :summary, :visibility, 'MANUAL',"
+                + " :relatedType, :relatedId, :occurredAt, :actor, :actor)")
+        .param("id", id)
+        .param("projectId", command.projectId())
+        .param("type", command.activityType())
+        .param("title", command.title().trim())
+        .param("summary", command.summary())
+        .param("visibility", command.visibility())
+        .param("relatedType", command.relatedResourceType())
+        .param("relatedId", command.relatedResourceId())
+        .param("occurredAt", java.sql.Timestamp.from(command.occurredAt()))
+        .param("actor", command.actor())
+        .update();
+    return find(command.projectId(), id)
+        .orElseThrow(
+            () -> new IllegalStateException("activity vanished right after insert: " + id));
+  }
+
+  @Override
+  public Optional<ProjectActivityView> update(UpdateProjectActivityCommand command) {
+    int updated =
+        jdbcClient
+            .sql(
+                "UPDATE project_activity SET title = :title, summary = :summary,"
+                    + " visibility = :visibility, occurred_at = :occurredAt,"
+                    + " version = version + 1, updated_at = now(), updated_by = :actor"
+                    + " WHERE id = :id AND project_id = :projectId AND version = :expected")
+            .param("id", command.activityId())
+            .param("projectId", command.projectId())
+            .param("expected", command.expectedVersion())
+            .param("title", command.title().trim())
+            .param("summary", command.summary())
+            .param("visibility", command.visibility())
+            .param("occurredAt", java.sql.Timestamp.from(command.occurredAt()))
+            .param("actor", command.actor())
+            .update();
+    return updated == 0 ? Optional.empty() : find(command.projectId(), command.activityId());
+  }
+
+  @Override
+  public int delete(UUID projectId, UUID activityId, long expectedVersion) {
+    return jdbcClient
+        .sql(
+            "DELETE FROM project_activity"
+                + " WHERE id = :id AND project_id = :projectId AND version = :expected")
+        .param("id", activityId)
+        .param("projectId", projectId)
+        .param("expected", expectedVersion)
+        .update();
+  }
+}

src/adapter/outbound/persistence-jpa/src/postgresqlIntegrationTest/java/dev/caskeleton/adapter/outbound/persistence/techlog/management/ManagementPersistenceIntegrationTest.java

@@ -5,12 +5,16 @@ import static org.assertj.core.api.Assertions.assertThat;
 import com.zaxxer.hikari.HikariConfig;
 import com.zaxxer.hikari.HikariDataSource;
 import dev.caskeleton.adapter.outbound.persistence.techlog.query.JdbcCatalogQueryAdapter;
+import dev.caskeleton.application.techlog.management.command.CreateProjectActivityCommand;
 import dev.caskeleton.application.techlog.management.command.CreateProjectCommand;
 import dev.caskeleton.application.techlog.management.command.UpdateHomeFocusCommand;
+import dev.caskeleton.application.techlog.management.command.UpdateProjectActivityCommand;
 import dev.caskeleton.application.techlog.management.model.HomeFocusConfigView;
+import dev.caskeleton.application.techlog.management.model.ProjectActivityView;
 import dev.caskeleton.application.techlog.management.model.ProjectEditView;
 import dev.caskeleton.application.techlog.studio.query.CatalogEntryType;
 import dev.caskeleton.application.techlog.studio.query.CatalogPageView;
+import java.time.Instant;
 import java.util.UUID;
 import org.flywaydb.core.Flyway;
 import org.junit.jupiter.api.AfterAll;
@@ -43,6 +47,7 @@ class ManagementPersistenceIntegrationTest {
   private static JdbcProjectRepositoryAdapter projects;
   private static JdbcHomeFocusConfigAdapter homeFocus;
   private static JdbcCatalogQueryAdapter catalog;
+  private static JdbcProjectActivityRepositoryAdapter activities;
 
   @BeforeAll
   static void migrate() {
@@ -75,6 +80,7 @@ class ManagementPersistenceIntegrationTest {
     projects = new JdbcProjectRepositoryAdapter(jdbcClient, new ObjectMapper());
     homeFocus = new JdbcHomeFocusConfigAdapter(jdbcClient);
     catalog = new JdbcCatalogQueryAdapter(jdbcClient);
+    activities = new JdbcProjectActivityRepositoryAdapter(jdbcClient);
   }
 
   @AfterAll
@@ -586,4 +592,106 @@ class ManagementPersistenceIntegrationTest {
         .extracting("id")
         .contains(caseId);
   }
+
+  // ---------------------------------------------------------------- 프로젝트 활동
+
+  private static ProjectActivityView addActivity(UUID projectId, String title, String visibility) {
+    return activities.create(
+        new CreateProjectActivityCommand(
+            projectId,
+            0L,
+            "MILESTONE_REACHED",
+            title,
+            "요약",
+            visibility,
+            null,
+            null,
+            Instant.parse("2026-08-23T00:00:00Z"),
+            "test"));
+  }
+
+  /**
+   * 공개 프로젝트 화면의 "활동" 은 이 테이블을 투영 없이 직접 읽는다. 그래서 여기서 만든 줄이 곧 그 화면이고, 편집기가 읽는 목록과 화면이 읽는 목록이 같은 정렬·같은
+   * 조건을 써야 한다.
+   */
+  @Test
+  void createdActivitiesAreVisibleToTheEditorAndToThePublicQuery() {
+    ProjectEditView project = projects.create(new CreateProjectCommand("Activity Host", "test"));
+    ProjectActivityView pub = addActivity(project.id(), "공개 활동", "PUBLIC");
+    addActivity(project.id(), "비공개 활동", "PRIVATE");
+
+    assertThat(pub.origin()).isEqualTo("MANUAL");
+    assertThat(activities.listByProject(project.id())).hasSize(2);
+
+    // 공개 조회가 쓰는 조건 그대로.
+    assertThat(
+            jdbcClient
+                .sql(
+                    "SELECT title FROM project_activity"
+                        + " WHERE project_id = :id AND visibility = 'PUBLIC'"
+                        + " ORDER BY occurred_at DESC, id DESC")
+                .param("id", project.id())
+                .query(String.class)
+                .list())
+        .containsExactly("공개 활동");
+  }
+
+  @Test
+  void activityUpdatesRoundTripAndRefuseAStaleVersion() {
+    ProjectEditView project = projects.create(new CreateProjectCommand("Activity Edit", "test"));
+    ProjectActivityView created = addActivity(project.id(), "처음 제목", "PRIVATE");
+
+    ProjectActivityView updated =
+        activities
+            .update(
+                new UpdateProjectActivityCommand(
+                    project.id(),
+                    created.id(),
+                    created.version(),
+                    "고친 제목",
+                    "고친 요약",
+                    "PUBLIC",
+                    Instant.parse("2026-08-24T00:00:00Z"),
+                    "test"))
+            .orElseThrow();
+
+    assertThat(updated.title()).isEqualTo("고친 제목");
+    assertThat(updated.visibility()).isEqualTo("PUBLIC");
+    assertThat(updated.version()).isEqualTo(created.version() + 1);
+
+    assertThat(
+            activities.update(
+                new UpdateProjectActivityCommand(
+                    project.id(),
+                    created.id(),
+                    created.version(),
+                    "다시",
+                    null,
+                    "PUBLIC",
+                    Instant.parse("2026-08-24T00:00:00Z"),
+                    "test")))
+        .isEmpty();
+  }
+
+  /** 경로가 프로젝트와 활동을 함께 요구하므로 저장소도 둘을 함께 본다 — 남의 프로젝트 줄을 고치거나 지울 수 없어야 한다. */
+  @Test
+  void activityWritesAreScopedToTheirOwnProject() {
+    ProjectEditView mine = projects.create(new CreateProjectCommand("Mine", "test"));
+    ProjectEditView theirs = projects.create(new CreateProjectCommand("Theirs", "test"));
+    ProjectActivityView activity = addActivity(theirs.id(), "남의 활동", "PUBLIC");
+
+    assertThat(activities.find(mine.id(), activity.id())).isEmpty();
+    assertThat(activities.delete(mine.id(), activity.id(), activity.version())).isZero();
+    assertThat(activities.find(theirs.id(), activity.id())).isPresent();
+  }
+
+  @Test
+  void deletingAnActivityHonoursTheExpectedVersion() {
+    ProjectEditView project = projects.create(new CreateProjectCommand("Activity Delete", "test"));
+    ProjectActivityView activity = addActivity(project.id(), "지울 활동", "PUBLIC");
+
+    assertThat(activities.delete(project.id(), activity.id(), activity.version() + 9)).isZero();
+    assertThat(activities.delete(project.id(), activity.id(), activity.version())).isEqualTo(1);
+    assertThat(activities.listByProject(project.id())).isEmpty();
+  }
 }

src/app-bootstrap/src/main/java/dev/caskeleton/bootstrap/techlog/TechLogManagementConfig.java

@@ -2,13 +2,16 @@ package dev.caskeleton.bootstrap.techlog;
 
 import dev.caskeleton.application.techlog.management.port.out.DocumentDeletionPort;
 import dev.caskeleton.application.techlog.management.port.out.HomeFocusConfigPort;
+import dev.caskeleton.application.techlog.management.port.out.ProjectActivityRepositoryPort;
 import dev.caskeleton.application.techlog.management.port.out.ProjectRepositoryPort;
 import dev.caskeleton.application.techlog.management.port.out.ReleaseRepositoryPort;
 import dev.caskeleton.application.techlog.management.port.out.TopicRepositoryPort;
 import dev.caskeleton.application.techlog.management.service.ArchiveReleaseUseCase;
+import dev.caskeleton.application.techlog.management.service.CreateProjectActivityUseCase;
 import dev.caskeleton.application.techlog.management.service.CreateProjectUseCase;
 import dev.caskeleton.application.techlog.management.service.CreateReleaseUseCase;
 import dev.caskeleton.application.techlog.management.service.DeleteDocumentDraftUseCase;
+import dev.caskeleton.application.techlog.management.service.DeleteProjectActivityUseCase;
 import dev.caskeleton.application.techlog.management.service.DeleteProjectDecisionUseCase;
 import dev.caskeleton.application.techlog.management.service.DeleteProjectUseCase;
 import dev.caskeleton.application.techlog.management.service.DeleteQuestionUseCase;
@@ -17,6 +20,7 @@ import dev.caskeleton.application.techlog.management.service.DeleteTopicUseCase;
 import dev.caskeleton.application.techlog.management.service.GetHomeFocusUseCase;
 import dev.caskeleton.application.techlog.management.service.GetProjectForEditUseCase;
 import dev.caskeleton.application.techlog.management.service.GetReleaseForEditUseCase;
+import dev.caskeleton.application.techlog.management.service.ListStudioProjectActivitiesUseCase;
 import dev.caskeleton.application.techlog.management.service.ListStudioProjectsUseCase;
 import dev.caskeleton.application.techlog.management.service.ListStudioReleasesUseCase;
 import dev.caskeleton.application.techlog.management.service.ListStudioTopicsUseCase;
@@ -25,6 +29,7 @@ import dev.caskeleton.application.techlog.management.service.PublishReleaseUseCa
 import dev.caskeleton.application.techlog.management.service.SaveTopicUseCase;
 import dev.caskeleton.application.techlog.management.service.UnpublishProjectUseCase;
 import dev.caskeleton.application.techlog.management.service.UpdateHomeFocusUseCase;
+import dev.caskeleton.application.techlog.management.service.UpdateProjectActivityUseCase;
 import dev.caskeleton.application.techlog.management.service.UpdateProjectUseCase;
 import dev.caskeleton.application.techlog.management.service.UpdateReleaseUseCase;
 import dev.caskeleton.application.transaction.TransactionPort;
@@ -154,4 +159,30 @@ public class TechLogManagementConfig {
   UpdateHomeFocusUseCase updateHomeFocusUseCase(HomeFocusConfigPort config, TransactionPort tx) {
     return new UpdateHomeFocusUseCase(config, tx);
   }
+
+  @Bean
+  ListStudioProjectActivitiesUseCase listStudioProjectActivitiesUseCase(
+      ProjectActivityRepositoryPort activities, TransactionPort tx) {
+    return new ListStudioProjectActivitiesUseCase(activities, tx);
+  }
+
+  @Bean
+  CreateProjectActivityUseCase createProjectActivityUseCase(
+      ProjectActivityRepositoryPort activities,
+      ProjectRepositoryPort projects,
+      TransactionPort tx) {
+    return new CreateProjectActivityUseCase(activities, projects, tx);
+  }
+
+  @Bean
+  UpdateProjectActivityUseCase updateProjectActivityUseCase(
+      ProjectActivityRepositoryPort activities, TransactionPort tx) {
+    return new UpdateProjectActivityUseCase(activities, tx);
+  }
+
+  @Bean
+  DeleteProjectActivityUseCase deleteProjectActivityUseCase(
+      ProjectActivityRepositoryPort activities, TransactionPort tx) {
+    return new DeleteProjectActivityUseCase(activities, tx);
+  }
 }

src/application-core/src/main/java/dev/caskeleton/application/techlog/management/command/CreateProjectActivityCommand.java

@@ -0,0 +1,19 @@
+package dev.caskeleton.application.techlog.management.command;
+
+import java.time.Instant;
+import java.util.UUID;
+
+/**
+ * {@code createProjectActivity}. {@code origin} 은 명령이 정하지 않는다 — 이 경로로 들어온 것은 언제나 {@code MANUAL} 이다.
+ */
+public record CreateProjectActivityCommand(
+    UUID projectId,
+    long expectedProjectVersion,
+    String activityType,
+    String title,
+    String summary,
+    String visibility,
+    String relatedResourceType,
+    UUID relatedResourceId,
+    Instant occurredAt,
+    String actor) {}

src/application-core/src/main/java/dev/caskeleton/application/techlog/management/command/UpdateProjectActivityCommand.java

@@ -0,0 +1,20 @@
+package dev.caskeleton.application.techlog.management.command;
+
+import java.time.Instant;
+import java.util.UUID;
+
+/**
+ * {@code updateProjectActivity}.
+ *
+ * <p>{@code activityType} 과 관련 자원은 고칠 수 없다 — 그것을 바꾸면 같은 줄이 다른 사건을 가리키게 된다. 바꿀 수 있는 것은 사람이 읽는
+ * 부분(제목·요약)과 노출 여부, 그리고 언제 일어난 일인지다.
+ */
+public record UpdateProjectActivityCommand(
+    UUID projectId,
+    UUID activityId,
+    long expectedVersion,
+    String title,
+    String summary,
+    String visibility,
+    Instant occurredAt,
+    String actor) {}

src/application-core/src/main/java/dev/caskeleton/application/techlog/management/model/ProjectActivityView.java

@@ -0,0 +1,23 @@
+package dev.caskeleton.application.techlog.management.model;
+
+import java.time.Instant;
+import java.util.UUID;
+
+/**
+ * 계약 {@code ProjectActivityResponse}.
+ *
+ * <p>{@code origin} 은 이 줄이 어디서 왔는지다 — 게시 같은 실제 사건이 남긴 {@code AUTO} 인지, 작성자가 손으로 적은 {@code MANUAL}
+ * 인지. 지우기가 그 둘을 다르게 다루므로 뷰에도 실어 보낸다.
+ */
+public record ProjectActivityView(
+    UUID id,
+    UUID projectId,
+    String activityType,
+    String title,
+    String summary,
+    String visibility,
+    String origin,
+    String relatedResourceType,
+    UUID relatedResourceId,
+    Instant occurredAt,
+    long version) {}

src/application-core/src/main/java/dev/caskeleton/application/techlog/management/port/out/ProjectActivityRepositoryPort.java

@@ -0,0 +1,25 @@
+package dev.caskeleton.application.techlog.management.port.out;
+
+import dev.caskeleton.application.techlog.management.command.CreateProjectActivityCommand;
+import dev.caskeleton.application.techlog.management.command.UpdateProjectActivityCommand;
+import dev.caskeleton.application.techlog.management.model.ProjectActivityView;
+import java.util.List;
+import java.util.Optional;
+import java.util.UUID;
+
+/** 프로젝트 활동의 편집용 읽기/쓰기. 공개 조회는 {@code publicsite} 쪽 포트가 따로 소유한다. */
+public interface ProjectActivityRepositoryPort {
+
+  /** 최근 것이 먼저다 — 공개 타임라인과 같은 정렬이라 편집기와 화면이 같은 순서를 본다. */
+  List<ProjectActivityView> listByProject(UUID projectId);
+
+  Optional<ProjectActivityView> find(UUID projectId, UUID activityId);
+
+  ProjectActivityView create(CreateProjectActivityCommand command);
+
+  /** 낙관적 잠금. 버전이 어긋나면 {@code Optional.empty()}. */
+  Optional<ProjectActivityView> update(UpdateProjectActivityCommand command);
+
+  /** 삭제된 행 수. 0 이면 없거나 버전이 어긋난 것이다. */
+  int delete(UUID projectId, UUID activityId, long expectedVersion);
+}

src/application-core/src/main/java/dev/caskeleton/application/techlog/management/service/CreateProjectActivityUseCase.java

@@ -0,0 +1,73 @@
+package dev.caskeleton.application.techlog.management.service;
+
+import dev.caskeleton.application.capability.Idempotency;
+import dev.caskeleton.application.capability.RepositoryAccess;
+import dev.caskeleton.application.capability.UseCaseCapability;
+import dev.caskeleton.application.security.RequiresPermission;
+import dev.caskeleton.application.techlog.error.ManagementError;
+import dev.caskeleton.application.techlog.error.ManagementException;
+import dev.caskeleton.application.techlog.management.command.CreateProjectActivityCommand;
+import dev.caskeleton.application.techlog.management.model.ProjectActivityView;
+import dev.caskeleton.application.techlog.management.model.ProjectEditView;
+import dev.caskeleton.application.techlog.management.port.out.ProjectActivityRepositoryPort;
+import dev.caskeleton.application.techlog.management.port.out.ProjectRepositoryPort;
+import dev.caskeleton.application.techlog.studio.service.StudioPermissions;
+import dev.caskeleton.application.transaction.TransactionMode;
+import dev.caskeleton.application.transaction.TransactionPort;
+import java.util.Objects;
+
+/**
+ * {@code createProjectActivity}.
+ *
+ * <p>{@code expectedProjectVersion} 은 활동이 아니라 <em>프로젝트</em>의 버전이다. 활동은 아직 없으므로 자기 버전을 가질 수 없고, 두
+ * 사람이 같은 프로젝트의 타임라인을 동시에 고치는 것을 막으려면 붙잡을 것이 프로젝트뿐이다.
+ */
+@RequiresPermission(StudioPermissions.WRITE)
+@UseCaseCapability(
+    transactionMode = TransactionMode.WRITE,
+    idempotency = Idempotency.NOT_IDEMPOTENT,
+    repositoryAccess = RepositoryAccess.WRITE_REPOSITORY)
+public class CreateProjectActivityUseCase {
+
+  private final ProjectActivityRepositoryPort activities;
+  private final ProjectRepositoryPort projects;
+  private final TransactionPort transactions;
+
+  public CreateProjectActivityUseCase(
+      ProjectActivityRepositoryPort activities,
+      ProjectRepositoryPort projects,
+      TransactionPort transactions) {
+    this.activities = Objects.requireNonNull(activities, "activities");
+    this.projects = Objects.requireNonNull(projects, "projects");
+    this.transactions = Objects.requireNonNull(transactions, "transactions");
+  }
+
+  public ProjectActivityView handle(CreateProjectActivityCommand command) {
+    Objects.requireNonNull(command, "command");
+    ProjectActivityUseCases.requireType(command.activityType());
+    ProjectActivityUseCases.requireVisibility(command.visibility());
+    ProjectActivityUseCases.requireTitle(command.title());
+    if (command.occurredAt() == null) {
+      throw ManagementException.of(
+          ManagementError.REQUEST_VALIDATION_FAILED, "occurredAt must not be null");
+    }
+
+    return transactions.inWrite(
+        () -> {
+          ProjectEditView project =
+              projects
+                  .find(command.projectId())
+                  .orElseThrow(
+                      () ->
+                          ManagementException.of(
+                              ManagementError.PROJECT_NOT_FOUND, "no such project"));
+          if (project.version() != command.expectedProjectVersion()) {
+            throw ManagementException.withDetails(
+                ManagementError.VERSION_CONFLICT,
+                "the project changed since it was loaded",
+                new SaveTopicUseCase.VersionConflict(project.version()));
+          }
+          return activities.create(command);
+        });
+  }
+}

src/application-core/src/main/java/dev/caskeleton/application/techlog/management/service/DeleteProjectActivityUseCase.java

@@ -0,0 +1,68 @@
+package dev.caskeleton.application.techlog.management.service;
+
+import dev.caskeleton.application.capability.Idempotency;
+import dev.caskeleton.application.capability.RepositoryAccess;
+import dev.caskeleton.application.capability.UseCaseCapability;
+import dev.caskeleton.application.security.RequiresPermission;
+import dev.caskeleton.application.techlog.error.ManagementError;
+import dev.caskeleton.application.techlog.error.ManagementException;
+import dev.caskeleton.application.techlog.management.model.ProjectActivityView;
+import dev.caskeleton.application.techlog.management.port.out.ProjectActivityRepositoryPort;
+import dev.caskeleton.application.techlog.studio.service.StudioPermissions;
+import dev.caskeleton.application.transaction.TransactionMode;
+import dev.caskeleton.application.transaction.TransactionPort;
+import java.util.Objects;
+import java.util.UUID;
+
+/**
+ * {@code deleteProjectActivity}.
+ *
+ * <p>{@code AUTO} 로 기록된 줄은 지우지 않는다. 그것은 게시 같은 실제 사건이 남긴 흔적이고, 지우면 무슨 일이 있었는지가 사라진다. 손으로 적은 {@code
+ * MANUAL} 줄만 지울 수 있다 — 잘못 적은 것을 되돌리는 것과 일어난 일을 없애는 것은 다르다.
+ */
+@RequiresPermission(StudioPermissions.WRITE)
+@UseCaseCapability(
+    transactionMode = TransactionMode.WRITE,
+    idempotency = Idempotency.NOT_IDEMPOTENT,
+    repositoryAccess = RepositoryAccess.WRITE_REPOSITORY)
+public class DeleteProjectActivityUseCase {
+
+  private final ProjectActivityRepositoryPort activities;
+  private final TransactionPort transactions;
+
+  public DeleteProjectActivityUseCase(
+      ProjectActivityRepositoryPort activities, TransactionPort transactions) {
+    this.activities = Objects.requireNonNull(activities, "activities");
+    this.transactions = Objects.requireNonNull(transactions, "transactions");
+  }
+
+  public void handle(UUID projectId, UUID activityId, long expectedVersion, String actor) {
+    Objects.requireNonNull(projectId, "projectId");
+    Objects.requireNonNull(activityId, "activityId");
+    Objects.requireNonNull(actor, "actor");
+
+    transactions.inWrite(
+        () -> {
+          ProjectActivityView current =
+              activities
+                  .find(projectId, activityId)
+                  .orElseThrow(
+                      () ->
+                          ManagementException.of(
+                              ManagementError.PROJECT_NOT_FOUND,
+                              "no such activity on this project"));
+          if (!"MANUAL".equals(current.origin())) {
+            throw ManagementException.of(
+                ManagementError.PROJECT_IN_USE,
+                "an automatically recorded activity cannot be deleted");
+          }
+          if (activities.delete(projectId, activityId, expectedVersion) == 0) {
+            throw ManagementException.withDetails(
+                ManagementError.VERSION_CONFLICT,
+                "the activity changed since it was loaded",
+                new SaveTopicUseCase.VersionConflict(current.version()));
+          }
+          return null;
+        });
+  }
+}

src/application-core/src/main/java/dev/caskeleton/application/techlog/management/service/ListStudioProjectActivitiesUseCase.java

@@ -0,0 +1,36 @@
+package dev.caskeleton.application.techlog.management.service;
+
+import dev.caskeleton.application.capability.Idempotency;
+import dev.caskeleton.application.capability.RepositoryAccess;
+import dev.caskeleton.application.capability.UseCaseCapability;
+import dev.caskeleton.application.security.RequiresPermission;
+import dev.caskeleton.application.techlog.management.model.ProjectActivityView;
+import dev.caskeleton.application.techlog.management.port.out.ProjectActivityRepositoryPort;
+import dev.caskeleton.application.techlog.studio.service.StudioPermissions;
+import dev.caskeleton.application.transaction.TransactionMode;
+import dev.caskeleton.application.transaction.TransactionPort;
+import java.util.List;
+import java.util.Objects;
+import java.util.UUID;
+
+@RequiresPermission(StudioPermissions.READ)
+@UseCaseCapability(
+    transactionMode = TransactionMode.READ_ONLY,
+    idempotency = Idempotency.IDEMPOTENT,
+    repositoryAccess = RepositoryAccess.READ_REPOSITORY)
+public class ListStudioProjectActivitiesUseCase {
+
+  private final ProjectActivityRepositoryPort activities;
+  private final TransactionPort transactions;
+
+  public ListStudioProjectActivitiesUseCase(
+      ProjectActivityRepositoryPort activities, TransactionPort transactions) {
+    this.activities = Objects.requireNonNull(activities, "activities");
+    this.transactions = Objects.requireNonNull(transactions, "transactions");
+  }
+
+  public List<ProjectActivityView> handle(UUID projectId) {
+    Objects.requireNonNull(projectId, "projectId");
+    return transactions.inRead(() -> activities.listByProject(projectId));
+  }
+}

src/application-core/src/main/java/dev/caskeleton/application/techlog/management/service/ProjectActivityUseCases.java

@@ -0,0 +1,51 @@
+package dev.caskeleton.application.techlog.management.service;
+
+import dev.caskeleton.application.techlog.error.ManagementError;
+import dev.caskeleton.application.techlog.error.ManagementException;
+import java.util.Set;
+
+/** 활동 use case 넷이 공유하는 규칙. 값의 허용 집합은 DB CHECK 제약과 같은 목록이다. */
+final class ProjectActivityUseCases {
+
+  /** {@code project_activity_activity_type_check} 와 같은 목록이다. */
+  static final Set<String> TYPES =
+      Set.of(
+          "PHASE_CHANGED",
+          "QUESTION_OPENED",
+          "QUESTION_RESOLVED",
+          "DECISION_ACCEPTED",
+          "CASE_PUBLISHED",
+          "REFERENCE_PUBLISHED",
+          "MILESTONE_REACHED",
+          "PROJECT_PAUSED",
+          "PROJECT_RESUMED");
+
+  static final Set<String> VISIBILITIES = Set.of("PRIVATE", "PUBLIC");
+
+  private ProjectActivityUseCases() {}
+
+  /*
+   * 제약 위반을 그대로 터뜨리지 않고 여기서 먼저 거절한다. 드라이버가 던지는 것은 벤더 메시지 문자열이고,
+   * 그것을 화면에 그대로 내보내면 작성자는 무엇을 고쳐야 하는지 알 수 없다.
+   */
+  static void requireType(String value) {
+    if (value == null || !TYPES.contains(value)) {
+      throw ManagementException.of(
+          ManagementError.REQUEST_VALIDATION_FAILED, "activityType is not a known activity type");
+    }
+  }
+
+  static void requireVisibility(String value) {
+    if (value == null || !VISIBILITIES.contains(value)) {
+      throw ManagementException.of(
+          ManagementError.REQUEST_VALIDATION_FAILED, "visibility must be PRIVATE or PUBLIC");
+    }
+  }
+
+  static void requireTitle(String value) {
+    if (value == null || value.isBlank()) {
+      throw ManagementException.of(
+          ManagementError.REQUEST_VALIDATION_FAILED, "title must not be blank");
+    }
+  }
+}

src/application-core/src/main/java/dev/caskeleton/application/techlog/management/service/UpdateProjectActivityUseCase.java

@@ -0,0 +1,63 @@
+package dev.caskeleton.application.techlog.management.service;
+
+import dev.caskeleton.application.capability.Idempotency;
+import dev.caskeleton.application.capability.RepositoryAccess;
+import dev.caskeleton.application.capability.UseCaseCapability;
+import dev.caskeleton.application.security.RequiresPermission;
+import dev.caskeleton.application.techlog.error.ManagementError;
+import dev.caskeleton.application.techlog.error.ManagementException;
+import dev.caskeleton.application.techlog.management.command.UpdateProjectActivityCommand;
+import dev.caskeleton.application.techlog.management.model.ProjectActivityView;
+import dev.caskeleton.application.techlog.management.port.out.ProjectActivityRepositoryPort;
+import dev.caskeleton.application.techlog.studio.service.StudioPermissions;
+import dev.caskeleton.application.transaction.TransactionMode;
+import dev.caskeleton.application.transaction.TransactionPort;
+import java.util.Objects;
+
+/** {@code updateProjectActivity}. */
+@RequiresPermission(StudioPermissions.WRITE)
+@UseCaseCapability(
+    transactionMode = TransactionMode.WRITE,
+    idempotency = Idempotency.NOT_IDEMPOTENT,
+    repositoryAccess = RepositoryAccess.WRITE_REPOSITORY)
+public class UpdateProjectActivityUseCase {
+
+  private final ProjectActivityRepositoryPort activities;
+  private final TransactionPort transactions;
+
+  public UpdateProjectActivityUseCase(
+      ProjectActivityRepositoryPort activities, TransactionPort transactions) {
+    this.activities = Objects.requireNonNull(activities, "activities");
+    this.transactions = Objects.requireNonNull(transactions, "transactions");
+  }
+
+  public ProjectActivityView handle(UpdateProjectActivityCommand command) {
+    Objects.requireNonNull(command, "command");
+    ProjectActivityUseCases.requireVisibility(command.visibility());
+    ProjectActivityUseCases.requireTitle(command.title());
+    if (command.occurredAt() == null) {
+      throw ManagementException.of(
+          ManagementError.REQUEST_VALIDATION_FAILED, "occurredAt must not be null");
+    }
+
+    return transactions.inWrite(
+        () -> {
+          ProjectActivityView current =
+              activities
+                  .find(command.projectId(), command.activityId())
+                  .orElseThrow(
+                      () ->
+                          ManagementException.of(
+                              ManagementError.PROJECT_NOT_FOUND,
+                              "no such activity on this project"));
+          return activities
+              .update(command)
+              .orElseThrow(
+                  () ->
+                      ManagementException.withDetails(
+                          ManagementError.VERSION_CONFLICT,
+                          "the activity changed since it was loaded",
+                          new SaveTopicUseCase.VersionConflict(current.version())));
+        });
+  }
+}

src/config/openapi/MANIFEST.sha256

@@ -1,6 +1,6 @@
-# source: tech-log-design-package contracts/openapi/studio-v1.yaml @ ed04872 (master)
+# source: tech-log-design-package contracts/openapi/studio-v1.yaml @ 436937f (master)
 6fc015ca6727af88b7fb0088e02ba97846e1dd79fb0d4fc593cc79f2a3b9795f  studio-v1.yaml
-# source: tech-log-design-package contracts/openapi/public-v1.yaml @ ed04872 (master)
+# source: tech-log-design-package contracts/openapi/public-v1.yaml @ 436937f (master)
 37e6f804165de3e492e975075bea563ee41ae74076222a3562d3452631bfdb2b  public-v1.yaml
-# source: tech-log-design-package contracts/openapi/studio-management-v1.yaml @ ed04872 (master)
+# source: tech-log-design-package contracts/openapi/studio-management-v1.yaml @ 436937f (master)
-c143ad3303eb05a02320940e2a0f5300a38b0c05f40b5bd5cf30960ef8004573  studio-management-v1.yaml
+72650735061fde627f5037571eb986cb758f44a546f065c88408399f8eec4a55  studio-management-v1.yaml

src/config/openapi/studio-management-v1.yaml

@@ -5101,33 +5101,31 @@ paths:
           content:
             application/json:
               schema:
-                type: array
+                $ref: '#/components/schemas/ProjectActivityListEnvelope'
-                items:
-                  $ref: '#/components/schemas/ProjectActivityResponse'
         '401':
           description: '401'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '403':
           description: '403'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '404':
           description: '404'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '500':
           description: '500'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
     post:
       operationId: createProjectActivity
       tags:
@@ -5154,49 +5152,49 @@ paths:
           content:
             application/json:
               schema:
-                $ref: '#/components/schemas/ProjectActivityResponse'
+                $ref: '#/components/schemas/ProjectActivityResponseEnvelope'
         '400':
           description: '400'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '401':
           description: '401'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '403':
           description: '403'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '404':
           description: '404'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '409':
           description: '409'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '422':
           description: '422'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '500':
           description: '500'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
   /api/v1/studio/projects/{id}/activities/{activityId}:
     put:
       operationId: updateProjectActivity
@@ -5230,49 +5228,126 @@ paths:
           content:
             application/json:
               schema:
-                $ref: '#/components/schemas/ProjectActivityResponse'
+                $ref: '#/components/schemas/ProjectActivityResponseEnvelope'
         '400':
           description: '400'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '401':
           description: '401'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '403':
           description: '403'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '404':
           description: '404'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '409':
           description: '409'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '422':
           description: '422'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
         '500':
           description: '500'
           content:
-            application/problem+json:
+            application/json:
               schema:
-                $ref: '#/components/schemas/ProblemDetails'
+                $ref: '#/components/schemas/ErrorEnvelope'
+    delete:
+      operationId: deleteProjectActivity
+      tags:
+      - Projects
+      description: |-
+        프로젝트 활동 한 줄을 지운다. 계약에는 만들기와 고치기만 있었고 지우기가 없어서, 잘못
+        적은 줄이 공개 타임라인에 영구히 남았다.
+
+        `AUTO` 로 기록된 줄은 게시 같은 실제 사건의 흔적이므로 지우지 않는다 — 지우면 무슨 일이
+        있었는지가 사라진다. 손으로 적은 `MANUAL` 줄만 지울 수 있다.
+      parameters:
+      - name: id
+        in: path
+        required: true
+        schema:
+          type: string
+          format: uuid
+      - name: activityId
+        in: path
+        required: true
+        schema:
+          type: string
+          format: uuid
+      - $ref: '#/components/parameters/CsrfToken'
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/ExpectedVersionRequest'
+      responses:
+        '204':
+          description: No Content
+        '400':
+          description: Bad Request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorEnvelope'
+        '401':
+          description: Unauthorized
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorEnvelope'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorEnvelope'
+        '404':
+          description: Not Found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorEnvelope'
+        '409':
+          description: Conflict
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorEnvelope'
+        '422':
+          description: Unprocessable Content
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorEnvelope'
+        '500':
+          description: Internal Server Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorEnvelope'
+      security:
+      - sessionCookie: []
 components:
   securitySchemes:
     sessionCookie:
@@ -5525,6 +5600,38 @@ components:
           $ref: '#/components/schemas/HomeFocusResponse'
         meta:
           $ref: '#/components/schemas/ResponseMeta'
+    ProjectActivityResponseEnvelope:
+      type: object
+      additionalProperties: false
+      required:
+      - success
+      - data
+      - meta
+      properties:
+        success:
+          type: boolean
+          const: true
+        data:
+          $ref: '#/components/schemas/ProjectActivityResponse'
+        meta:
+          $ref: '#/components/schemas/ResponseMeta'
+    ProjectActivityListEnvelope:
+      type: object
+      additionalProperties: false
+      required:
+      - success
+      - data
+      - meta
+      properties:
+        success:
+          type: boolean
+          const: true
+        data:
+          type: array
+          items:
+            $ref: '#/components/schemas/ProjectActivityResponse'
+        meta:
+          $ref: '#/components/schemas/ResponseMeta'
     PublishResponseEnvelope:
       type: object
       additionalProperties: false