Add per-product pause/resume checking feature

Users can now pause and resume price checking for individual products
or in bulk via the Actions menu.

Backend:
- Added checking_paused column to products table
- Scheduler skips products with checking_paused=true
- Added POST /products/bulk/pause endpoint for bulk pause/resume

Frontend:
- Added Pause Checking and Resume Checking to bulk Actions menu
- Added filter dropdown (All/Active/Paused) next to sort controls
- Paused products show greyed out with pause icon and "Paused" label
- Progress bar hidden when paused

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

backend/src/index.ts

@@ -191,6 +191,10 @@ async function runMigrations() {
         IF NOT EXISTS (SELECT 1 FROM information_schema.columns WHERE table_name = 'products' AND column_name = 'ai_extraction_disabled') THEN
           ALTER TABLE products ADD COLUMN ai_extraction_disabled BOOLEAN DEFAULT false;
         END IF;
+        -- Per-product checking pause flag
+        IF NOT EXISTS (SELECT 1 FROM information_schema.columns WHERE table_name = 'products' AND column_name = 'checking_paused') THEN
+          ALTER TABLE products ADD COLUMN checking_paused BOOLEAN DEFAULT false;
+        END IF;
       END $$;
     `);
 

backend/src/models/index.ts

@@ -344,6 +344,7 @@ export interface Product {
   notify_back_in_stock: boolean;
   ai_verification_disabled: boolean;
   ai_extraction_disabled: boolean;
+  checking_paused: boolean;
   created_at: Date;
 }
 
@@ -587,8 +588,8 @@ export const productQueries = {
   findDueForRefresh: async (): Promise<Product[]> => {
     const result = await pool.query(
       `SELECT * FROM products
-       WHERE next_check_at IS NULL
-       OR next_check_at < CURRENT_TIMESTAMP`
+       WHERE (next_check_at IS NULL OR next_check_at < CURRENT_TIMESTAMP)
+       AND (checking_paused IS NULL OR checking_paused = false)`
     );
     return result.rows;
   },
@@ -638,6 +639,15 @@ export const productQueries = {
     );
     return result.rows[0]?.ai_extraction_disabled === true;
   },
+
+  bulkSetCheckingPaused: async (ids: number[], userId: number, paused: boolean): Promise<number> => {
+    if (ids.length === 0) return 0;
+    const result = await pool.query(
+      `UPDATE products SET checking_paused = $1 WHERE id = ANY($2) AND user_id = $3`,
+      [paused, ids, userId]
+    );
+    return result.rowCount || 0;
+  },
 };
 
 // Price History types and queries

backend/src/routes/products.ts

@@ -268,4 +268,31 @@ router.delete('/:id', async (req: AuthRequest, res: Response) => {
   }
 });
 
+// Bulk pause/resume checking
+router.post('/bulk/pause', async (req: AuthRequest, res: Response) => {
+  try {
+    const userId = req.userId!;
+    const { ids, paused } = req.body;
+
+    if (!Array.isArray(ids) || ids.length === 0) {
+      res.status(400).json({ error: 'Product IDs array is required' });
+      return;
+    }
+
+    if (typeof paused !== 'boolean') {
+      res.status(400).json({ error: 'Paused status (boolean) is required' });
+      return;
+    }
+
+    const updated = await productQueries.bulkSetCheckingPaused(ids, userId, paused);
+    res.json({
+      message: `${updated} product(s) ${paused ? 'paused' : 'resumed'}`,
+      updated
+    });
+  } catch (error) {
+    console.error('Error bulk updating pause status:', error);
+    res.status(500).json({ error: 'Failed to update pause status' });
+  }
+});
+
 export default router;