docs: Add database protection warning to CLAUDE.md

[evansenter]

Summary

• Adds prominent warning section to CLAUDE.md about database protection
• Documents that ~/.claude/contrib/analytics/data.db contains irreplaceable historical data
• Lists forbidden operations (DROP TABLE, DELETE FROM user tables, file deletion)
• Lists safe operations (DELETE FROM patterns, make uninstall/reinstall)
• Notes that tests use temporary databases

Test plan

• Verified no existing code can drop the database
• All 205 tests pass

🤖 Generated with Claude Code

[claude]

PR Review: docs: Add database protection warning to CLAUDE.md

Summary

This PR adds a prominent warning section to CLAUDE.md that protects the database from accidental deletion. This is excellent documentation that will help prevent future data loss.

Feedback

Strengths:

1. Well-placed: The warning is positioned prominently after the Architecture section, making it visible to anyone reading the file
2. Clear categorization: The distinction between "NEVER" and "Safe operations" is helpful and actionable
3. Accurate documentation: Verified against the codebase:
   • DELETE FROM patterns is indeed the only delete operation in storage.py (lines 921, 924)
   • All 5 test files use tmpdir/tmp_path fixtures for temporary databases
   • The git_commits table exists in the schema (line 491)
4. Emoji warning: The ⚠️ emoji is appropriate here as it draws attention to critical safety information

Minor suggestions (non-blocking):

1. Consider adding session_commits to the list of protected tables in the "NEVER" section, since it's also user data (stores session-to-commit mappings):

   - Add `DROP TABLE` statements for `events`, `sessions`, `ingested_files`, `git_commits`, or `session_commits`

2. The "If you need to test destructive operations" section could optionally mention that pytest automatically handles this through the existing fixtures.

Verification

• The DELETE FROM statements in storage.py only target patterns table
• No os.remove(), unlink(), or DROP TABLE for user data exists in the codebase
• All tests use temporary databases via tmpdir/tmp_path

Verdict

LGTM - This is valuable documentation that will help protect irreplaceable user data. The minor suggestion about session_commits is optional and can be addressed in a follow-up if desired.