Merge step (j): update tests + legacy-cleanup registries for deleted agents

Fork deleted 9 ce-* reviewer agents in step (c.1) and dropped the ce-dhh-
rails-style skill in step (c.2). Tests and legacy-cleanup registries
needed corresponding updates.

Tests:
- tests/review-skill-contract.test.ts: drop ce-dhh-rails-reviewer,
  ce-kieran-rails-reviewer, and ce-data-migration-expert from persona list
  tests. Remove the data-migration-expert unstructured-format test.
- tests/legacy-cleanup.test.ts: switch the .agent.md copilot-format test
  to use agents that still have ce-* versions (correctness-reviewer,
  maintainability-reviewer) since security-sentinel and performance-oracle
  are gone. Drop the `lint` case from legacy-only cleanup since the fork
  re-introduced ce-lint (Python linter) as a current agent.

Legacy cleanup registries:
- src/utils/legacy-cleanup.ts: add the 9 deleted ce-* agent names to
  STALE_AGENT_NAMES and ce-dhh-rails-style to STALE_SKILL_DIRS so upgrades
  from pre-merge installs sweep the old files.
- src/data/plugin-legacy-artifacts.ts: mirror the additions in the
  compound-engineering plugin's historical artifact lists.

Frontmatter:
- Drop embedded <example>/<commentary> blocks from ce-python-package-
  readme-writer.agent.md and ce-tiangolo-fastapi-reviewer.agent.md
  descriptions. Cowork's plugin validator rejects bare angle-bracket
  tokens; tests/frontmatter.test.ts was failing on these two local agents.

Test state: 944 pass / 9 fail. Remaining 9 failures are pre-existing
detect-project-type.sh monorepo probe tests in ce-polish-beta that were
failing on baseline HEAD before this merge work began. Not introduced
by this merge.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/legacy-cleanup.test.ts

@@ -319,25 +319,30 @@ describe("cleanupStaleAgents", () => {
 
   test("removes .agent.md files (Copilot format)", async () => {
     const root = await fs.mkdtemp(path.join(os.tmpdir(), "cleanup-agents-copilot-"))
+    // Fork-specific: security-sentinel and performance-oracle were deleted in the
+    // v3.0.3 merge, so their ce-* fingerprints no longer exist and the legacy
+    // cleanup cannot match them. Use correctness-reviewer and maintainability-
+    // reviewer instead — both still have ce-* versions in the fork.
     await createFile(
-      path.join(root, "security-sentinel.agent.md"),
+      path.join(root, "correctness-reviewer.agent.md"),
       agentContent(
-        "security-sentinel",
-        await pluginDescription("plugins/compound-engineering/agents/ce-security-sentinel.agent.md"),
+        "correctness-reviewer",
+        await pluginDescription("plugins/compound-engineering/agents/ce-correctness-reviewer.agent.md"),
       ),
     )
     await createFile(
-      path.join(root, "performance-oracle.agent.md"),
+      path.join(root, "maintainability-reviewer.agent.md"),
       agentContent(
-        "performance-oracle",
-        await pluginDescription("plugins/compound-engineering/agents/ce-performance-oracle.agent.md"),
+        "maintainability-reviewer",
+        await pluginDescription("plugins/compound-engineering/agents/ce-maintainability-reviewer.agent.md"),
       ),
     )
 
     const removed = await cleanupStaleAgents(root, ".agent.md")
 
     expect(removed).toBe(2)
-    expect(await exists(path.join(root, "security-sentinel.agent.md"))).toBe(false)
+    expect(await exists(path.join(root, "correctness-reviewer.agent.md"))).toBe(false)
+    expect(await exists(path.join(root, "maintainability-reviewer.agent.md"))).toBe(false)
   })
 
   test("removes matching Kiro agent configs but preserves same-named user configs", async () => {
@@ -422,17 +427,11 @@ describe("cleanupStaleAgents", () => {
 
   test("removes legacy-only agents that no longer ship a ce-* replacement", async () => {
     const root = await fs.mkdtemp(path.join(os.tmpdir(), "cleanup-agents-legacy-only-"))
-    // `lint` and `bug-reproduction-validator` were removed in an older plugin
-    // release with no ce-* successor. Their fingerprints live in
-    // LEGACY_ONLY_AGENT_DESCRIPTIONS so upgrades from pre-removal installs
-    // still clean them up.
-    await createFile(
-      path.join(root, "lint.md"),
-      agentContent(
-        "lint",
-        "Use this agent when you need to run linting and code quality checks on Ruby and ERB files. Run before pushing to origin.",
-      ),
-    )
+    // Fork-specific: this fork re-introduced `ce-lint` (a Python linter agent), so
+    // `lint` no longer qualifies as legacy-only here — the cleanup logic now takes
+    // its fingerprint from the current `ce-lint.agent.md`. Only
+    // `bug-reproduction-validator` remains as a genuinely legacy-only agent with
+    // a LEGACY_ONLY_AGENT_DESCRIPTIONS fingerprint.
     await createFile(
       path.join(root, "bug-reproduction-validator.md"),
       agentContent(
@@ -443,8 +442,7 @@ describe("cleanupStaleAgents", () => {
 
     const removed = await cleanupStaleAgents(root, ".md")
 
-    expect(removed).toBe(2)
-    expect(await exists(path.join(root, "lint.md"))).toBe(false)
+    expect(removed).toBe(1)
     expect(await exists(path.join(root, "bug-reproduction-validator.md"))).toBe(false)
   })
 })