Add PR splitting strategy documentation for complex CI failures

Document comprehensive strategy for breaking large PRs into smaller,
more manageable pieces when facing multiple CI test failures.

New Document: .claude/docs/pr-splitting-strategy.md

Key Sections:

1. When to Split a Large PR
   - Indicators: multiple failures, 50+ commits, mixed concerns
   - Decision criteria and time investment thresholds
   - Real example: PR #2069 with 52 commits, 3 failures + 1 hung

2. Strategy for Splitting
   - Identify independent commits
   - Determine merge order (docs → bug fixes → infrastructure)
   - Create focused PRs with clear scope
   - Handle original PR (close vs rebase)

3. Real-World Example: PR #2069 Split Plan
   - PR 1: Documentation (merge first, zero risk)
   - PR 2: buildConsoleReplay fix (focused bug fix)
   - PR 3: Workspace dependencies (small infrastructure)
   - PR 4: Monorepo node renderer (defer, most complex)

4. Benefits & Anti-Patterns
   - Benefits: easier review, incremental progress, better debugging
   - Anti-patterns: splitting too much, dependent changes, no testing
   - Decision tree for when to split

5. Templates & Timelines
   - PR split announcement template
   - Real-world 4-week timeline example
   - Incremental progress vs stuck on one PR

Updated: .claude/docs/analysis/INDEX.md
- Added pr-splitting-strategy.md as document #6
- Added to quick navigation: "Decide whether to split a large PR"
- Listed in related documentation section

Rationale:
When facing complex PRs with multiple CI failures (like PR #2069):
- 52 commits make bisecting difficult
- Multiple unrelated failures (integration, Pro, hung tests)
- Estimated 4-8 hours to fix all issues
- Some parts can provide value independently

Splitting allows:
- Merge low-risk changes (docs) immediately
- Review focused changes more easily
- Incremental progress instead of being blocked
- Better attribution if new issues arise
- Unblock dependent work

This strategy applies to any large PR with multiple failures, not just
monorepo work. Provides decision framework and concrete examples.

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

Co-Authored-By: Claude <[email protected]>

Author: justin808

.claude/docs/analysis/INDEX.md

@@ -83,13 +83,46 @@ Suggested improvements for developer experience in monorepo context.
 
 **Use when**: Reviewing documentation enhancement opportunities
 
+### 6. pr-splitting-strategy.md (STRATEGIC - 12 KB)
+
+**Strategy guide for breaking large PRs into smaller ones**
+
+Contains:
+
+- When to split a large PR (indicators and decision criteria)
+- Strategy for identifying independent commits
+- Step-by-step splitting process
+- Real-world example: How to split PR #2069
+- Benefits, anti-patterns, and decision tree
+- Template for announcing PR splits
+
+**Use when**: Facing complex CI failures in large PRs, planning PR strategy, deciding whether to split
+
+---
+
+## Related Documentation
+
+Outside the analysis directory:
+
+- **PR Splitting Strategy**: `/.claude/docs/pr-splitting-strategy.md` (splitting large PRs)
+- **Main Migration Plan**: `/docs/MONOREPO_MERGER_PLAN.md` (authoritative source)
+- **Path Management Guide**: `/.claude/docs/managing-file-paths.md` (validation procedures)
+- **Build Script Testing**: `/.claude/docs/testing-build-scripts.md` (artifact verification)
+- **CI Monitoring**: `/.claude/docs/master-health-monitoring.md` (CI status checks)
+- **Contributing Guide**: `/CONTRIBUTING.md` (developer instructions)
+
+---
+
 ## Quick Navigation
 
 ### I Need To...
 
 **Fix current CI failures**
 → Read: CI_FAILURES_2024-11-21.md (MOST URGENT)
 
+**Decide whether to split a large PR**
+→ Read: pr-splitting-strategy.md (for complex PRs with multiple failures)
+
 **Understand the current state**
 → Read: Executive Summary in MONOREPO_MIGRATION_ANALYSIS.md