feat(catalog): brand search, parts pagination, and parts search

Backend:
- Add 'search' param to /brand-parts endpoint (filters oem_part_number and name via ILIKE)
- Keep count query accurate with search filter

Frontend (brand-catalog.js):
- Brand search input: filters 619 brands locally while typing
- Parts pagination: Previous/Next buttons with page counter (50 per page)
- Parts search within category: search input + Enter key triggers backend search
- Visual polish: stock badges, empty-state messages, responsive layout
- Loading states and breadcrumbs improved

pos/blueprints/catalog_bp.py

@@ -663,9 +663,10 @@ def brand_categories():
 @catalog_bp.route('/brand-parts', methods=['GET'])
 @require_auth('catalog.view')
 def brand_parts():
-    """Return parts for a given vehicle brand + category."""
+    """Return parts for a given vehicle brand + category, optionally filtered by search term."""
     brand = request.args.get('brand', '')
     category_id = request.args.get('category_id', type=int)
+    search = request.args.get('search', '').strip()
     limit = request.args.get('limit', 50, type=int)
     offset = request.args.get('offset', 0, type=int)
 
@@ -675,13 +676,22 @@ def brand_parts():
     def _query(master, tenant, branch_id):
         cur = master.cursor()
         try:
-            # Get parts from the brand catalog
+            # Build dynamic filters
             params = [brand]
             cat_filter = ""
+            search_filter = ""
+
             if category_id:
                 cat_filter = "AND pc.id_part_category = %s"
                 params.append(category_id)
 
+            if search:
+                search_filter = "AND (p.oem_part_number ILIKE %s OR COALESCE(NULLIF(p.name_es, ''), p.name_part) ILIKE %s)"
+                like_term = f"%{search}%"
+                params.extend([like_term, like_term])
+
+            # Get parts from the brand catalog
+            query_params = list(params)
             cur.execute(f"""
                 SELECT DISTINCT p.id_part, p.oem_part_number,
                        COALESCE(NULLIF(p.name_es, ''), p.name_part) as name,
@@ -693,9 +703,10 @@ def brand_parts():
                 JOIN part_categories pc ON pc.id_part_category = pg.category_id
                 WHERE pvp.name_brand = %s
                 {cat_filter}
+                {search_filter}
                 ORDER BY p.id_part
                 LIMIT %s OFFSET %s
-            """, params + [limit, offset])
+            """, query_params + [limit, offset])
 
             part_rows = cur.fetchall()
             part_ids = [r[0] for r in part_rows]
@@ -709,6 +720,7 @@ def brand_parts():
                 JOIN part_categories pc ON pc.id_part_category = pg.category_id
                 WHERE pvp.name_brand = %s
                 {cat_filter}
+                {search_filter}
             """, params)
             total = cur.fetchone()[0]
 
@@ -738,6 +750,7 @@ def brand_parts():
             return jsonify({
                 'brand': brand,
                 'category_id': category_id,
+                'search': search,
                 'items': items,
                 'total': total,
                 'limit': limit,