fix: keep line breaks in the fields that are not Markdown

The earlier fix covered the Markdown body and stopped there, so the preview
still ran lines together — which is exactly what it looked like from the
outside: nothing had changed.

Summary, problem, conclusion, environment and the rest are plain text. They
never pass through the Markdown parser, so their newlines sit in a text node
and HTML collapses them, and the renderer that now emits <br> for the body was
never asked about them.

They render through the same rule now. One helper, one behaviour: a line the
author broke stays broken, wherever they typed it.

src/features/tech-log/presentation/shared/public-render/inline-renderer.tsx

@@ -33,6 +33,15 @@ function renderText(text: string, key: number) {
   );
 }
 
+/**
+ * 작성자가 직접 쓴 평문. 요약·문제·결론·환경처럼 Markdown 을 거치지 않고 그대로 그려지는 칸들이
+ * 여기 온다 — 그 칸들은 텍스트 노드에 줄바꿈이 그대로 들어가고, HTML 이 그것을 공백으로 접어
+ * 작성자가 나눠 쓴 줄이 이어져 보였다. 본문(Markdown)만 고쳤을 때 이 칸들이 남아 있던 이유다.
+ */
+export function PlainText({ text }: { text: string }) {
+  return renderText(text, 0);
+}
+
 function renderInline(inline: Inline, key: number) {
   switch (inline.type) {
     case "TEXT":

src/features/tech-log/presentation/shared/public-render/public-record-renderer.tsx

@@ -2,6 +2,7 @@ import { Link } from "react-router-dom";
 
 import type { components } from "../../../contracts/studio/generated.ts";
 import { inlinePlainText } from "../../../domain/content-format/inline-plain-text.ts";
+import { PlainText } from "./inline-renderer.tsx";
 import type {
   ResolveEvidenceAsset,
   ResolvePublishedLabel,
@@ -92,7 +93,7 @@ function ModelDocumentHeader({
         ) : null}
       </nav>
       <h1>{model.title}</h1>
-      <p>{model.summary}</p>
+      <p><PlainText text={model.summary} /></p>
       <dl>
         <div>
           <dt>유형</dt>
@@ -149,21 +150,21 @@ function GenericCase({
       <section className="document-snapshot" aria-label="문제와 결론">
         <div>
           <p className="snapshot-label">문제</p>
-          <p>{model.problem}</p>
+          <p><PlainText text={model.problem} /></p>
         </div>
         <div>
           <p className="snapshot-label snapshot-label--answer">결론</p>
-          <p>{model.conclusion}</p>
+          <p><PlainText text={model.conclusion} /></p>
         </div>
       </section>
       <dl className="document-facts">
         <div>
           <dt>검증 환경</dt>
-          <dd>{model.environment}</dd>
+          <dd><PlainText text={model.environment} /></dd>
         </div>
         <div>
           <dt>검증 데이터</dt>
-          <dd>{model.reproduction}</dd>
+          <dd><PlainText text={model.reproduction} /></dd>
         </div>
       </dl>
       <article className="public-document-body">
@@ -213,27 +214,27 @@ function FetchJoinCase({
         </nav>
 
         <h1>{model.title}</h1>
-        <p className="case-summary">{model.summary}</p>
+        <p className="case-summary"><PlainText text={model.summary} /></p>
 
         <section className="case-snapshot" aria-label="문제와 결론">
           <div>
             <p className="snapshot-label">문제</p>
-            <p>{model.problem}</p>
+            <p><PlainText text={model.problem} /></p>
           </div>
           <div>
             <p className="snapshot-label snapshot-label--answer">결론</p>
-            <p>{model.conclusion}</p>
+            <p><PlainText text={model.conclusion} /></p>
           </div>
         </section>
 
         <dl className="case-meta">
           <div>
             <dt>검증 환경</dt>
-            <dd>{model.environment}</dd>
+            <dd><PlainText text={model.environment} /></dd>
           </div>
           <div>
             <dt>데이터셋</dt>
-            <dd>{model.reproduction.replace(/^Dataset:\s*/, "")}</dd>
+            <dd><PlainText text={model.reproduction.replace(/^Dataset:\s*/, "")} /></dd>
           </div>
           <div>
             <dt>기록</dt>
@@ -287,7 +288,7 @@ function ReferenceDocument({
       <section className="reference-purpose" aria-labelledby="purpose-title">
         <p className="section-kicker">Purpose</p>
         <h2 id="purpose-title">이 기준을 쓰는 이유</h2>
-        <p>{model.purpose}</p>
+        <p><PlainText text={model.purpose} /></p>
       </section>
       <article className="public-document-body reference-body">
         <section aria-labelledby="rules-title">
@@ -434,7 +435,7 @@ function QuestionDocument({
         >
           <p className="section-kicker">Next</p>
           <h2 id="next-validation-title">다음 검증</h2>
-          <p>{model.nextValidation}</p>
+          <p><PlainText text={model.nextValidation} /></p>
         </section>
       </article>
       <PublicDocumentRelations relations={publicRelations(model.relations)} />
@@ -476,11 +477,11 @@ function ProjectDecisionDocument({
                 <time dateTime={model.decidedOn}>{displayDate(model.decidedOn)}</time>
               </div>
               <h2>{model.title}</h2>
-              <p>{model.statement}</p>
+              <p><PlainText text={model.statement} /></p>
             </header>
             <section>
               <h3>판단 이유</h3>
-              <p>{model.rationale}</p>
+              <p><PlainText text={model.rationale} /></p>
             </section>
             <section>
               <h3>영향</h3>

tests/component/inline-line-breaks.test.tsx

@@ -3,7 +3,10 @@
 import { render } from "@testing-library/react";
 import { describe, expect, it } from "vitest";
 
-import { InlineRenderer } from "../../src/features/tech-log/presentation/shared/public-render/inline-renderer.tsx";
+import {
+  InlineRenderer,
+  PlainText,
+} from "../../src/features/tech-log/presentation/shared/public-render/inline-renderer.tsx";
 
 /**
  * 작성자가 엔터로 나눠 쓴 글이 한 줄로 이어져 보였다. Markdown 이 한 번의 줄바꿈을 문단 내 공백으로
@@ -34,3 +37,19 @@ describe("문단 안의 줄바꿈", () => {
     expect(container.querySelectorAll("br")).toHaveLength(2);
   });
 });
+
+/**
+ * 요약·문제·결론·환경은 Markdown 을 거치지 않고 그대로 그려진다. 본문만 고쳤을 때 이 칸들이
+ * 여전히 이어져 보인 이유이고, 작성자가 "아직 안 고쳐졌다" 고 본 것도 이쪽이다.
+ */
+describe("Markdown 을 거치지 않는 평문 칸", () => {
+  it("작성자가 나눠 쓴 줄을 지킨다", () => {
+    const { container } = render(<PlainText text={"문제 첫 줄\n문제 둘째 줄"} />);
+    expect(container.querySelectorAll("br")).toHaveLength(1);
+  });
+
+  it("한 줄이면 <br> 를 넣지 않는다", () => {
+    const { container } = render(<PlainText text="한 줄" />);
+    expect(container.querySelectorAll("br")).toHaveLength(0);
+  });
+});