feat: MercadoLibre integration + inventory bulk publish + WhatsApp bridge fixes

- Add MercadoLibre OAuth, listings, orders, webhooks and category search
- New marketplace_external_bp.py, meli_service.py, marketplace_external_service.py
- New marketplace_external.html/js with ML management UI
- Inventory: bulk publish to ML with category autocomplete, listing type and shipping selectors
- Inventory: new .btn--meli styles, select/label CSS fixes
- WhatsApp bridge: rate limiting, 440/515/408 error handling, stale watchdog
- DB migration v3.4_meli_integration.sql for marketplace_listings, orders, sync_queue
- Add Celery tasks for ML sync and webhook processing
- Sidebar: MercadoLibre navigation link

pos/services/wa_quotation.py

@@ -135,41 +135,34 @@ def _ensure_sessions_table(tenant_conn):
     cur.close()
 
 
-def set_last_shown_part(phone, part_info):
+def set_last_shown_part(tenant_conn, phone, part_info):
     """Store the last part shown to this phone number.
 
     part_info: dict with keys inventory_id, part_number, name, brand,
     price, stock, unit
     """
-    # In-memory fallback for when tenant_conn is not available
-    from tenant_db import get_tenant_conn
     try:
-        conn = get_tenant_conn(11)
-        _ensure_sessions_table(conn)
-        cur = conn.cursor()
+        _ensure_sessions_table(tenant_conn)
+        cur = tenant_conn.cursor()
         import json
         cur.execute("""
             INSERT INTO whatsapp_sessions (phone, last_shown, updated_at)
             VALUES (%s, %s, NOW())
             ON CONFLICT (phone) DO UPDATE SET last_shown = EXCLUDED.last_shown, updated_at = NOW()
         """, (phone, json.dumps(part_info)))
-        conn.commit()
+        tenant_conn.commit()
         cur.close()
-        conn.close()
     except Exception as e:
         print(f"[WA-SESSION] Failed to persist last_shown for {phone}: {e}")
 
 
-def get_last_shown_part(phone):
-    from tenant_db import get_tenant_conn
+def get_last_shown_part(tenant_conn, phone):
     try:
-        conn = get_tenant_conn(11)
-        _ensure_sessions_table(conn)
-        cur = conn.cursor()
+        _ensure_sessions_table(tenant_conn)
+        cur = tenant_conn.cursor()
         cur.execute("SELECT last_shown FROM whatsapp_sessions WHERE phone = %s", (phone,))
         row = cur.fetchone()
         cur.close()
-        conn.close()
         if row and row[0]:
             return row[0]
     except Exception as e:
@@ -177,54 +170,45 @@ def get_last_shown_part(phone):
     return None
 
 
-def clear_last_shown(phone):
-    from tenant_db import get_tenant_conn
+def clear_last_shown(tenant_conn, phone):
     try:
-        conn = get_tenant_conn(11)
-        _ensure_sessions_table(conn)
-        cur = conn.cursor()
+        _ensure_sessions_table(tenant_conn)
+        cur = tenant_conn.cursor()
         cur.execute("DELETE FROM whatsapp_sessions WHERE phone = %s", (phone,))
-        conn.commit()
+        tenant_conn.commit()
         cur.close()
-        conn.close()
     except Exception as e:
         print(f"[WA-SESSION] Failed to clear last_shown for {phone}: {e}")
 
 
-def set_vehicle(phone, vehicle):
+def set_vehicle(tenant_conn, phone, vehicle):
     """Store the detected vehicle for this phone number.
 
     vehicle: dict with keys brand, model, year
     """
-    from tenant_db import get_tenant_conn
     try:
-        conn = get_tenant_conn(11)
-        _ensure_sessions_table(conn)
-        cur = conn.cursor()
+        _ensure_sessions_table(tenant_conn)
+        cur = tenant_conn.cursor()
         import json
         cur.execute("""
             INSERT INTO whatsapp_sessions (phone, vehicle, updated_at)
             VALUES (%s, %s, NOW())
             ON CONFLICT (phone) DO UPDATE SET vehicle = EXCLUDED.vehicle, updated_at = NOW()
         """, (phone, json.dumps(vehicle)))
-        conn.commit()
+        tenant_conn.commit()
         cur.close()
-        conn.close()
     except Exception as e:
         print(f"[WA-SESSION] Failed to persist vehicle for {phone}: {e}")
 
 
-def get_vehicle(phone):
+def get_vehicle(tenant_conn, phone):
     """Retrieve the stored vehicle for this phone number."""
-    from tenant_db import get_tenant_conn
     try:
-        conn = get_tenant_conn(11)
-        _ensure_sessions_table(conn)
-        cur = conn.cursor()
+        _ensure_sessions_table(tenant_conn)
+        cur = tenant_conn.cursor()
         cur.execute("SELECT vehicle FROM whatsapp_sessions WHERE phone = %s", (phone,))
         row = cur.fetchone()
         cur.close()
-        conn.close()
         if row and row[0]:
             return row[0]
     except Exception as e:
@@ -232,17 +216,14 @@ def get_vehicle(phone):
     return None
 
 
-def clear_session(phone):
+def clear_session(tenant_conn, phone):
     """Clear all session data (last_shown + vehicle) for this phone."""
-    from tenant_db import get_tenant_conn
     try:
-        conn = get_tenant_conn(11)
-        _ensure_sessions_table(conn)
-        cur = conn.cursor()
+        _ensure_sessions_table(tenant_conn)
+        cur = tenant_conn.cursor()
         cur.execute("DELETE FROM whatsapp_sessions WHERE phone = %s", (phone,))
-        conn.commit()
+        tenant_conn.commit()
         cur.close()
-        conn.close()
     except Exception as e:
         print(f"[WA-SESSION] Failed to clear session for {phone}: {e}")