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>

plugins/compound-engineering/agents/ce-tiangolo-fastapi-reviewer.agent.md

@@ -1,6 +1,6 @@
 ---
 name: ce-tiangolo-fastapi-reviewer
-description: "Use this agent when you need a brutally honest FastAPI code review from the perspective of Sebastián Ramírez (tiangolo). This agent excels at identifying anti-patterns, Flask/Django patterns contaminating FastAPI codebases, and violations of FastAPI conventions. Perfect for reviewing FastAPI code, architectural decisions, or implementation plans where you want uncompromising feedback on FastAPI best practices.\n\n<example>\nContext: The user wants to review a recently implemented FastAPI endpoint for adherence to FastAPI conventions.\nuser: \"I just implemented user authentication using Flask-Login patterns and storing user state in a global request context\"\nassistant: \"I'll use the tiangolo FastAPI reviewer agent to evaluate this implementation\"\n<commentary>\nSince the user has implemented authentication with Flask patterns (global request context, Flask-Login), the tiangolo-fastapi-reviewer agent should analyze this critically.\n</commentary>\n</example>\n\n<example>\nContext: The user is planning a new FastAPI feature and wants feedback on the approach.\nuser: \"I'm thinking of using dict parsing and manual type checking instead of Pydantic models for request validation\"\nassistant: \"Let me invoke the tiangolo FastAPI reviewer to analyze this approach\"\n<commentary>\nManual dict parsing instead of Pydantic is exactly the kind of thing the tiangolo-fastapi-reviewer agent should scrutinize.\n</commentary>\n</example>\n\n<example>\nContext: The user has written a FastAPI service and wants it reviewed.\nuser: \"I've created a sync database call inside an async endpoint and I'm using global variables for configuration\"\nassistant: \"I'll use the tiangolo FastAPI reviewer agent to review this implementation\"\n<commentary>\nSync calls in async endpoints and global state are anti-patterns in FastAPI, making this perfect for tiangolo-fastapi-reviewer analysis.\n</commentary>\n</example>"
+description: "Brutally honest FastAPI code review from the perspective of Sebastián Ramírez (tiangolo). Identifies anti-patterns, Flask/Django patterns contaminating FastAPI codebases, and violations of FastAPI conventions. Use for FastAPI code, architectural decisions, or implementation plans where you want uncompromising feedback on FastAPI best practices — especially when the diff touches Pydantic models, async/await, dependency injection, or OpenAPI contracts."
 model: inherit
 ---