Enhance lock acquisition and error handling in worker service

- Implement retry logic for acquiring file lock with a maximum of 3 attempts.
- Improve error handling for ENOENT errors by ensuring the directory exists before retrying.
- Update context injection handler to delegate to SearchRoutes, reducing code duplication and preventing "headers already sent" errors.
- Add checks for headersSent in error responses to avoid sending multiple responses.
- Log warnings when the port does not free up after shutdown, and handle forced shutdown scenarios more gracefully.

src/services/worker/http/BaseRouteHandler.ts

@@ -74,9 +74,12 @@ export abstract class BaseRouteHandler {
 
   /**
    * Centralized error logging and response
+   * Checks headersSent to avoid "Cannot set headers after they are sent" errors
    */
   protected handleError(res: Response, error: Error, context?: string): void {
     logger.failure('WORKER', context || 'Request failed', {}, error);
-    res.status(500).json({ error: error.message });
+    if (!res.headersSent) {
+      res.status(500).json({ error: error.message });
+    }
   }
 }