feat(plugins): implement Sprint 5 documentation and fixes (#266-#269)

Release v5.2.0

Documentation:
- Add git-flow branching strategy guide (docs/BRANCHING-STRATEGY.md)
- Add clarity-assist ND support documentation (docs/ND-SUPPORT.md)
- Update DEBUGGING-CHECKLIST.md with Gitea auto-close behavior and MCP restart notes
- Update plugin READMEs to reference new documentation

Bug Fix:
- Add milestone parameter to update_issue MCP tool (gitea_client.py, server.py, tools/issues.py)

Version Updates:
- Marketplace version: 5.1.0 → 5.2.0
- README title: v5.1.0 → v5.2.0
- CHANGELOG: [Unreleased] → [5.2.0] - 2026-01-28

Closes #266, Closes #267, Closes #268, Closes #269

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -1,4 +1,4 @@
-# Leo Claude Marketplace - v5.1.0
+# Leo Claude Marketplace - v5.2.0
 
 A collection of Claude Code plugins for project management, infrastructure automation, and development workflows.