Add local config files to .gitignore

- .claude/ - Claude Code workspace directory
- .mcp.json - User-specific MCP configuration
- PHASE3-PLAN-SUMMARY.md - Temporary planning document

These files contain local paths and should not be tracked in version control.

.gitignore

@@ -292,3 +292,8 @@ nadlan_mcp/__pycache__/
 nadlan_mcp/.env
 nadlan_mcp/.env.*
 nadlan_mcp/local_settings.py
+
+# Claude Code workspace and local config
+.claude/
+.mcp.json
+PHASE3-PLAN-SUMMARY.md