fix: Remove legacy imports from task handlers

- Remove non-existent DutchieClient import from product-resync and entry-point-discovery
- Remove non-existent DiscoveryCrawler import from store-discovery
- Use scrapeStore from scraper-v2 for product resync
- Use discoverState from discovery module for store discovery
- Fix Pool type by using getPool() instead of pool wrapper
- Update FullDiscoveryResult property access to use correct field names

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/tasks/task-worker.ts

@@ -17,7 +17,7 @@
 import { Pool } from 'pg';
 import { v4 as uuidv4 } from 'uuid';
 import { taskService, TaskRole, WorkerTask } from './task-service';
-import { pool } from '../db/pool';
+import { getPool } from '../db/pool';
 
 // Task handlers by role
 import { handleProductResync } from './handlers/product-resync';
@@ -64,7 +64,7 @@ export class TaskWorker {
   private currentTask: WorkerTask | null = null;
 
   constructor(role: TaskRole, workerId?: string) {
-    this.pool = pool;
+    this.pool = getPool();
     this.role = role;
     this.workerId = workerId || `worker-${role}-${uuidv4().slice(0, 8)}`;
   }