feat: configure ready outreach funnel limit

src/database/candidate-queue-repository.ts

@@ -191,12 +191,22 @@ export class CandidateQueueRepository {
     `).run(now, postId, workerId).changes === 1;
   }
 
-  promoteDueRetries(now: number = Date.now()): number {
+  promoteDueRetries(maxReadyCandidates: number, now: number = Date.now()): number {
+    if (!Number.isInteger(maxReadyCandidates) || maxReadyCandidates < 1) {
+      throw new Error('Maximum ready candidates must be a positive integer');
+    }
+    const capacity = maxReadyCandidates - this.countReady();
+    if (capacity <= 0) return 0;
     return this.db.prepare(`
       UPDATE candidate_queue
       SET status = 'ready', updated_at = ?, assigned_account_id = NULL
-      WHERE status = 'retryable' AND available_at <= ?
-    `).run(now, now).changes;
+      WHERE post_id IN (
+        SELECT post_id FROM candidate_queue
+        WHERE status = 'retryable' AND available_at <= ?
+        ORDER BY priority DESC, discovered_at ASC
+        LIMIT ?
+      )
+    `).run(now, now, capacity).changes;
   }
 
   recoverExpiredLeases(now: number = Date.now(), sendingDelayMs = 10 * 60_000): number {