fix: complete TechLog migration evidence

tests/features/tech-log/public-discovery-screens.test.tsx

@@ -372,18 +372,20 @@ describe("TechLog explore discovery", () => {
     ).toHaveAttribute("href", "/explore");
   });
 
-  it("renders an unknown kind as the source production plain 404", async () => {
+  it("keeps the unreachable unknown-kind client fallback accessible", async () => {
     const { router, container } = renderDiscoveryRoute(
       "TECH_LOG_EXPLORE_KIND",
       "/explore/unknown",
     );
 
     expect(router.state.location.pathname).toBe("/explore/unknown");
-    expect(await screen.findByText("Not Found", { exact: true })).toBeVisible();
+    expect(
+      await screen.findByRole("heading", { name: "페이지를 찾을 수 없습니다." }),
+    ).toBeVisible();
     expect(
       screen.queryByRole("heading", { name: "화면을 표시하지 못했습니다." }),
     ).not.toBeInTheDocument();
-    expect(container.querySelector(".site-frame")).toBeNull();
+    expect(container.querySelector(".site-frame")).not.toBeNull();
   });
 
   it("recovers a rejecting registered not-found runtime under its own chunk contract", async () => {

tests/features/tech-log/public-document-screens.test.tsx

@@ -337,12 +337,14 @@ describe("TechLog topics and Public not-found routing", () => {
     ["TECH_LOG_REFERENCE" as const, "/references/not-registered"],
     ["TECH_LOG_QUESTION" as const, "/questions/not-registered"],
     ["TECH_LOG_TOPIC" as const, "/topics/not-registered"],
-  ])("uses the source production plain 404 for %s", async (routeId, path) => {
+  ])("keeps the unreachable client fallback accessible for %s", async (routeId, path) => {
     const { container, router } = renderDocumentRoute(routeId, path);
 
     expect(router.state.location.pathname).toBe(path);
-    expect(await screen.findByText("Not Found", { exact: true })).toBeVisible();
+    expect(
+      await screen.findByRole("heading", { name: "페이지를 찾을 수 없습니다." }),
+    ).toBeVisible();
     expect(screen.queryByRole("heading", { name: "화면을 표시하지 못했습니다." })).not.toBeInTheDocument();
-    expect(container.querySelector(".site-frame")).toBeNull();
+    expect(container.querySelector(".site-frame")).not.toBeNull();
   });
 });

tests/features/tech-log/public-index-screens.test.tsx

@@ -360,25 +360,29 @@ describe("TechLog Public not-found runtime", () => {
     ["TECH_LOG_PROJECT_RECORDS" as const, "/projects/missing-project/records"],
     ["TECH_LOG_RELEASE" as const, "/releases/9.9.9"],
     ["TECH_LOG_CASE" as const, "/cases/not-registered"],
-  ])("renders the source-compatible plain fallback for %s", async (routeId, path) => {
+  ])("keeps the client-only fallback accessible for %s", async (routeId, path) => {
     const { container, router } = renderPublicRoute(routeId, path);
 
     expect(router.state.location.pathname).toBe(path);
-    expect(await screen.findByText("Not Found", { exact: true })).toBeVisible();
+    expect(
+      await screen.findByRole("heading", { name: "페이지를 찾을 수 없습니다." }),
+    ).toBeVisible();
     expect(
       screen.queryByRole("heading", { name: "화면을 표시하지 못했습니다." }),
     ).not.toBeInTheDocument();
-    expect(container.querySelector(".site-frame")).toBeNull();
+    expect(container.querySelector(".site-frame")).not.toBeNull();
   });
 
-  it("renders the source-compatible plain fallback for the Public catch-all", () => {
+  it("keeps the client-only Public catch-all accessible", () => {
     const { container, router } = renderPublicRoute(
       "NOT_FOUND",
       "/definitely-not-a-product-route",
     );
 
     expect(router.state.location.pathname).toBe("/definitely-not-a-product-route");
-    expect(screen.getByText("Not Found", { exact: true })).toBeVisible();
-    expect(container.querySelector(".site-frame")).toBeNull();
+    expect(
+      screen.getByRole("heading", { name: "페이지를 찾을 수 없습니다." }),
+    ).toBeVisible();
+    expect(container.querySelector(".site-frame")).not.toBeNull();
   });
 });