docs(tooling): add PR review and component pattern learnings to agent guides

[Kneesal]

Background

During the Bible Quotes Carousel implementation (#364 / PR #365), several recurring patterns and gotchas were identified that should be captured in agent guides and skills to prevent future rework.

Expected outcome

Learnings documented in the appropriate scoped files so agents can reference them in future work.

Acceptance criteria

• handle-pr-review/SKILL.md updated with CodeRabbit multi-endpoint checking and bot suggestion verification guidance
• apps/web/AGENTS.md updated with base-ui Button render prop, shadcn generated code gotchas, and string fallback patterns
• apps/cms/AGENTS.md updated with seed script idempotency guidance for nested components

Possible solution(s)

1. Add new sections to existing skill and AGENTS.md files

References

• PR feat(web): implement Bible Quotes Carousel section component #365 (Bible Quotes Carousel) — where learnings originated
• Issue feat(web): implement Bible Quotes Carousel section component #364