perf: Use denormalized product_count in pipeline and favorites routes

- pipeline.ts: Replace correlated subquery with d.product_count
- consumer-favorites.ts: Replace correlated subquery with d.product_count

Correlated subqueries were causing N+1 query patterns. Using the
denormalized column is O(1) lookup per row.

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

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

backend/src/routes/consumer-favorites.ts

@@ -75,6 +75,7 @@ router.get('/', async (req: Request, res: Response) => {
       });
     } else if (domain === 'findadispo.com') {
       // Dispensary favorites
+      // Use denormalized product_count column (faster than correlated subquery)
       const result = await pool.query(
         `SELECT f.*,
                 d.name as current_name,
@@ -88,7 +89,7 @@ router.get('/', async (req: Request, res: Response) => {
                 d.hours,
                 d.latitude,
                 d.longitude,
-                (SELECT COUNT(*) FROM store_products WHERE dispensary_id = d.id AND stock_status = 'in_stock') as product_count
+                COALESCE(d.product_count, 0) as product_count
          FROM findadispo_favorites f
          LEFT JOIN dispensaries d ON f.dispensary_id = d.id
          WHERE f.user_id = $1

backend/src/routes/pipeline.ts

@@ -679,11 +679,11 @@ router.post('/stores/:id/approve', async (req: Request, res: Response) => {
   const dispensaryId = parseInt(id, 10);
 
   try {
-    // Get the dispensary with product count
+    // Get the dispensary with product count (use denormalized column)
     const { rows } = await pool.query(`
       SELECT d.*,
         dcp.id as profile_id,
-        (SELECT COUNT(*) FROM store_products sp WHERE sp.dispensary_id = d.id) as product_count
+        COALESCE(d.product_count, 0) as product_count
       FROM dispensaries d
       LEFT JOIN dispensary_crawler_profiles dcp ON dcp.dispensary_id = d.id AND dcp.enabled = true
       WHERE d.id = $1
@@ -760,7 +760,7 @@ router.post('/stores/approve-batch', async (req: Request, res: Response) => {
   try {
     let query = `
       SELECT d.id, d.name,
-        (SELECT COUNT(*) FROM store_products sp WHERE sp.dispensary_id = d.id) as product_count
+        COALESCE(d.product_count, 0) as product_count
       FROM dispensaries d
       WHERE d.stage = 'sandbox'
     `;