Add documentation for CI failure analysis and PR splitting strategy

This PR contains only documentation changes extracted from PR #2069.
Zero risk - no code changes, just valuable documentation for the team.

New Documentation Added:

1. CI Failure Analysis (.claude/docs/analysis/CI_FAILURES_2024-11-21.md)
   - Comprehensive analysis of PR #2069 test failures
   - Root cause analysis with evidence from CI logs
   - Identified suspicious commits
   - Fix recommendations (all marked UNTESTED HYPOTHESIS)
   - Prevention strategies
   - CRITICAL DISCLAIMER: Analysis from isolated workspace

2. Testing Requirements (CLAUDE.md)
   - New section: "CRITICAL - LOCAL TESTING REQUIREMENTS"
   - Must distinguish "This fixes" vs "This SHOULD fix"
   - Must explain why local testing isn't possible
   - Must provide test commands
   - Must document what was tested
   - Enhanced "Replicating CI Failures Locally" section

3. PR Splitting Strategy (.claude/docs/pr-splitting-strategy.md)
   - When to split large PRs (indicators, decision criteria)
   - Strategy for identifying independent commits
   - Step-by-step splitting process
   - Real example: How to split PR #2069
   - Benefits, anti-patterns, decision tree
   - Templates for PR split announcements

4. Analysis Index (.claude/docs/analysis/INDEX.md)
   - Added new documents to navigation
   - Updated quick reference links

Why This Matters:

- Documents actual CI failures for future reference
- Establishes clear requirements for testing vs hypothetical fixes
- Provides framework for handling complex PRs with multiple failures
- All future AI work will distinguish tested vs untested fixes
- Team has strategy for breaking up large problematic PRs

Testing: None required (documentation only)

Related: PR #2069 (monorepo-completion) which will not merge

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808