docs: Remove temporary AI-generated files and add documentation guidelines

Remove temporary work artifacts that don't provide lasting value:
- MIGRATION_SUMMARY.md (migration process notes)
- PR_REVIEW_RESPONSE_PLAN.md (review response planning)
- REVIEW_RESPONSE.md (review response notes)

These files were AI-generated intermediate work products that belong
in PR descriptions/comments or git commit messages, not in the repository.

Add new section to CLAUDE.md: "When to Create Documentation Files"
Provides clear guidance on:
- What should be top-level .md files (user docs, standards)
- What should NOT be top-level files (temporary artifacts, PR context)
- Where to put that content instead (commits, PRs, issues, docs/)

Addresses review feedback about avoiding generic AI-generated markdown files
that clutter the repository without providing user value.

Author: jwm4

CLAUDE.md

@@ -893,6 +893,40 @@ Special lab track for leadership training located in `docs/labs/director-trainin
 - Structured exercises for understanding the vTeam system from a strategic perspective
 - Validation reports for tracking completion and understanding
 
+### When to Create Documentation Files
+
+**DO create top-level `.md` files when:**
+
+- **User-facing documentation**: `README.md`, `QUICK_START.md`, `CONTRIBUTING.md`
+- **Coding standards**: `CLAUDE.md`, `BRANCH_PROTECTION.md`
+- **Important architectural decisions**: ADRs that users/contributors need to reference
+- **The file provides lasting value** to anyone using or contributing to the repo
+
+**DO NOT create top-level `.md` files for:**
+
+- **Temporary work artifacts**: Migration summaries, review response plans, analysis notes
+- **PR-specific context**: This belongs in PR description or comments, not repo files
+- **AI brainstorming output**: Planning documents, strategy explorations, intermediate analysis
+- **Process documentation**: How a specific PR was reviewed/developed
+
+**Instead, put that content:**
+
+- **Git commit messages**: Detailed explanation of what/why you changed
+- **PR descriptions**: Context about the feature, trade-offs, testing approach
+- **PR comments**: Responses to reviews, clarifications, discussion
+- **Issue descriptions**: Track future work, document known limitations
+- **Docs folder**: `docs/` for substantial guides that aren't top-level worthy
+
+**The test:** Would a new developer or user in 6 months need this file? If not, it's temporary context that belongs in git history or GitHub discussions, not the repository root.
+
+**Examples of good top-level docs in this repo:**
+
+- `README.md` - Project overview, installation, usage
+- `QUICK_START.md` - Get running in 5 minutes
+- `CONTRIBUTING.md` - How to contribute code
+- `CLAUDE.md` - Coding standards and patterns
+- `BRANCH_PROTECTION.md` - Git workflow and protection rules
+
 ## Production Considerations
 
 ### Security