feat: Refactor Settings and Viewer routes to extend BaseRouteHandler for improved error handling

- Introduced BaseRouteHandler class to centralize error handling and response management.
- Updated SettingsRoutes to use wrapHandler for automatic error logging and response.
- Refactored ViewerRoutes to extend BaseRouteHandler and utilize wrapHandler for health check and UI serving.
- Enhanced error handling in SettingsRoutes and ViewerRoutes for better maintainability and readability.

src/services/worker/http/BaseRouteHandler.ts

@@ -0,0 +1,82 @@
+/**
+ * BaseRouteHandler
+ *
+ * Base class for all route handlers providing:
+ * - Automatic try-catch wrapping with error logging
+ * - Integer parameter validation
+ * - Required body parameter validation
+ * - Standard HTTP response helpers
+ * - Centralized error handling
+ */
+
+import { Request, Response } from 'express';
+import { logger } from '../../../utils/logger.js';
+
+export abstract class BaseRouteHandler {
+  /**
+   * Wrap handler with automatic try-catch and error logging
+   */
+  protected wrapHandler(
+    handler: (req: Request, res: Response) => void | Promise<void>
+  ): (req: Request, res: Response) => void {
+    return (req: Request, res: Response): void => {
+      try {
+        const result = handler(req, res);
+        if (result instanceof Promise) {
+          result.catch(error => this.handleError(res, error as Error));
+        }
+      } catch (error) {
+        this.handleError(res, error as Error);
+      }
+    };
+  }
+
+  /**
+   * Parse and validate integer parameter
+   * Returns the integer value or sends 400 error response
+   */
+  protected parseIntParam(req: Request, res: Response, paramName: string): number | null {
+    const value = parseInt(req.params[paramName], 10);
+    if (isNaN(value)) {
+      this.badRequest(res, `Invalid ${paramName}`);
+      return null;
+    }
+    return value;
+  }
+
+  /**
+   * Validate required body parameters
+   * Returns true if all required params present, sends 400 error otherwise
+   */
+  protected validateRequired(req: Request, res: Response, params: string[]): boolean {
+    for (const param of params) {
+      if (req.body[param] === undefined || req.body[param] === null) {
+        this.badRequest(res, `Missing ${param}`);
+        return false;
+      }
+    }
+    return true;
+  }
+
+  /**
+   * Send 400 Bad Request response
+   */
+  protected badRequest(res: Response, message: string): void {
+    res.status(400).json({ error: message });
+  }
+
+  /**
+   * Send 404 Not Found response
+   */
+  protected notFound(res: Response, message: string): void {
+    res.status(404).json({ error: message });
+  }
+
+  /**
+   * Centralized error logging and response
+   */
+  protected handleError(res: Response, error: Error, context?: string): void {
+    logger.failure('WORKER', context || 'Request failed', {}, error);
+    res.status(500).json({ error: error.message });
+  }
+}