add Google News integration and enhance crawler capabilities

config.json

@@ -42,8 +42,7 @@
     "googleNews": "0 * * * *"
   },
   "contentBackfill": {
-    "cron": "0 * * * *",
-    "batchSize": -1
+    "concurrency": 10
   },
   "googleNews": {
     "queries": [

src/scheduler.js

@@ -97,7 +97,8 @@ function startScheduler() {
       }
 
       try {
-        await backfillMissingContent();
+        const concurrency = Number(config.contentBackfill?.concurrency) || 5;
+        await backfillMissingContent(-1, concurrency);
       } catch (error) {
         console.error('content backfill failed:', error);
       }