feat(pos): sistema de imagenes — upload, thumbnail, display en inventario y catalogo

- Add POST/DELETE /items/{id}/image endpoints with Pillow processing (resize 800px, thumbnail 300px, JPEG 85%)
- Validate file type (jpg/png/webp) and size (max 5MB)
- Show image in product detail modal with upload/delete buttons
- Enrich catalog parts list with local inventory image when available
- Image directory created automatically on first upload (pos/static/images/parts/)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pos/services/catalog_service.py

@@ -271,12 +271,14 @@ def get_parts(master_conn, mye_id, group_id, tenant_conn, branch_id, page=1, per
         part_id = r[0]
         oem = r[1]
         local = local_map.get(oem) or local_map.get(f'cat:{part_id}')
+        # Prefer local inventory image over catalog image
+        image_url = (local.get('image_url') if local else None) or r[6]
         items.append({
             'id_part': part_id,
             'oem_part_number': oem,
             'name': r[3] or r[2],  # prefer Spanish name
             'description': r[5] or r[4],
-            'image_url': r[6],
+            'image_url': image_url,
             'local_stock': local['stock'] if local else 0,
             'local_price': local['price_1'] if local else None,
             'bodega_count': bodega_map.get(part_id, 0),
@@ -558,7 +560,8 @@ def _get_local_stock_bulk(tenant_conn, branch_id, oem_numbers, catalog_part_ids)
     cur.execute(f"""
         SELECT i.id, i.part_number, i.catalog_part_id,
                i.price_1, i.price_2, i.price_3, i.cost, i.tax_rate,
-               COALESCE(SUM(io.quantity), 0) AS stock
+               COALESCE(SUM(io.quantity), 0) AS stock,
+               i.image_url
         FROM inventory i
         LEFT JOIN inventory_operations io ON io.inventory_id = i.id
         WHERE ({where}) AND i.is_active = true{branch_filter}
@@ -577,6 +580,7 @@ def _get_local_stock_bulk(tenant_conn, branch_id, oem_numbers, catalog_part_ids)
             'cost': float(r[6]) if r[6] else 0,
             'tax_rate': float(r[7]) if r[7] else 0.16,
             'stock': r[8],
+            'image_url': r[9],
         }
         if r[1]:
             result[r[1]] = entry
@@ -598,7 +602,8 @@ def _get_local_stock_single(tenant_conn, branch_id, oem_part_number, catalog_par
     cur.execute(f"""
         SELECT i.id, i.price_1, i.price_2, i.price_3, i.cost, i.tax_rate,
                i.location, i.unit, i.barcode,
-               COALESCE(SUM(io.quantity), 0) AS stock
+               COALESCE(SUM(io.quantity), 0) AS stock,
+               i.image_url
         FROM inventory i
         LEFT JOIN inventory_operations io ON io.inventory_id = i.id
         WHERE (i.part_number = %s OR i.catalog_part_id = %s)
@@ -624,6 +629,7 @@ def _get_local_stock_single(tenant_conn, branch_id, oem_part_number, catalog_par
         'unit': row[7] or 'PZA',
         'barcode': row[8],
         'stock': row[9],
+        'image_url': row[10],
     }