chore(security): ignore local mcp.json configs

.cursor/mcp.json и .mcp.json в gitignore; убраны из индекса; example без секрета.

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -28,3 +28,7 @@ Thumbs.db
 
 # Compose runtime log sidecar output (deploy/compose/runtime-logs)
 deploy/compose/runtime-logs/
+# Local MCP configs (may contain REUI license Bearer)
+.cursor/mcp.json
+.mcp.json
+.codegraph/daemon.pid