refactor(gtm-audit): Update desktop skill to use Chrome DevTools + DTM Agent MCP workflow

- Replace Playwright-based approach with Chrome DevTools MCP for browser inspection
- Add DTM Agent MCP integration for GTM API operations
- Document 4-phase workflow: Inspect → Diagnose → Configure → Verify
- Add common issue patterns with diagnosis/fix guidance
- Update audit checklist to reference specific MCP tools
- Add .gitignore entries for pickle files and .claude/ directory

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

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

.gitignore

@@ -76,8 +76,13 @@ npm-debug.log*
 .env.local
 *.key
 *.pem
+*.pickle
 credentials.json
 secrets.json
+token.json
+
+# Claude Code local config
+.claude/
 
 # Temporary files
 output/