fix: replace console.log/console.error with proper logging in monitoring and themes routes

- monitoring.js: Added log dependency, replaced console.log with log.warn
- themes.js: Added log dependency, replaced console.error with log.error
- src/app.js: Pass log to monitoringRoutes and themesRoutes

This fixes error messages being lost to stdout instead of proper log files.

dashcaddy-api/routes/themes.js

@@ -8,9 +8,10 @@ const { ValidationError, NotFoundError } = require('../errors');
  * Themes routes factory
  * @param {Object} deps - Explicit dependencies
  * @param {Function} deps.asyncHandler - Async route handler wrapper
+ * @param {Object} deps.log - Logger instance
  * @returns {express.Router}
  */
-module.exports = function({ asyncHandler }) {
+module.exports = function({ asyncHandler, log }) {
   const router = express.Router();
   const THEMES_DIR = process.env.THEMES_DIR || path.join(path.dirname(process.env.SERVICES_FILE || '/app/services.json'), 'themes');
 
@@ -29,7 +30,7 @@ module.exports = function({ asyncHandler }) {
         themes[slug] = data;
       }
     } catch (e) {
-      console.error('[Themes] Failed to read themes:', e.message);
+      log.error('themes', 'Failed to read themes', { error: e.message });
     }
     return themes;
   }