fix: ML shipping config check + improved payload + actionable error messages

- Add get_shipping_preferences to meli_service.py
- Add check_meli_shipping_config to validate ME2 adoption before publishing
- Include local_pick_up and free_shipping in item payload
- Translate ME2/mode errors to actionable Spanish messages
- Check shipping config in both validate_items and publish_items

pos/services/marketplace_external_service.py

@@ -120,6 +120,12 @@ def _extract_meli_error(err: MeliError) -> str:
             if cause_msgs:
                 msg = (msg + " | " if msg else "") + "; ".join(cause_msgs)
         if msg:
+            # Translate common account-configuration errors to actionable messages
+            lowered = msg.lower()
+            if "me2 adoption is mandatory" in lowered:
+                return msg + " | Debes activar MercadoEnvíos (ME2) en tu cuenta de MercadoLibre. Ve a Configuración > Envíos en el panel de vendedor de ML."
+            if "user has not mode" in lowered:
+                return msg + " | Tu cuenta no tiene configurado este modo de envío. Configura tus métodos de envío en MercadoLibre."
             return msg
     except Exception:
         pass
@@ -153,7 +159,7 @@ def build_item_payload(
         "listing_type_id": listing_type_id,
         "condition": "new",
         "pictures": [{"source": url} for url in images if url],
-        "shipping": {"mode": shipping_mode},
+        "shipping": {"mode": shipping_mode, "local_pick_up": False, "free_shipping": False},
         "attributes": [],
     }
 
@@ -196,6 +202,34 @@ def build_item_payload(
     return payload
 
 
+def check_meli_shipping_config(svc: MeliService, cfg: dict) -> dict:
+    """Check if the user's ML account has the required shipping modes configured.
+
+    Returns {"ok": True} or {"ok": False, "error": "...", "available_modes": [...]}.
+    """
+    user_id = cfg.get("meli_user_id")
+    if not user_id:
+        return {"ok": False, "error": "Usuario de ML no configurado"}
+    try:
+        prefs = svc.get_shipping_preferences(str(user_id))
+        modes = prefs.get("modes", [])
+        mandatory = prefs.get("mandatory_mode_for_user", [])
+        if mandatory and not any(m in modes for m in mandatory):
+            return {
+                "ok": False,
+                "error": f"Tu cuenta requiere obligatoriamente los modos de envío: {', '.join(mandatory)}. Actualmente solo tienes: {', '.join(modes)}. Configúralos en el panel de vendedor de MercadoLibre.",
+                "available_modes": modes,
+                "mandatory_modes": mandatory,
+            }
+        return {"ok": True, "available_modes": modes, "mandatory_modes": mandatory}
+    except MeliError as e:
+        logger.warning("Failed to fetch shipping preferences: %s", e)
+        return {"ok": True}  # Don't block on preference fetch failure
+    except Exception as e:
+        logger.warning("Failed to fetch shipping preferences: %s", e)
+        return {"ok": True}
+
+
 # ═══════════════════════════════════════════════════════════════════════════
 # LISTINGS CRUD
 # ═══════════════════════════════════════════════════════════════════════════
@@ -279,6 +313,10 @@ def validate_items(
     if not svc:
         raise ValueError("MercadoLibre not configured")
 
+    shipping_check = check_meli_shipping_config(svc, cfg)
+    if not shipping_check["ok"]:
+        return {"valid": [], "invalid": [{"inventory_id": "config", "error": shipping_check["error"]}]}
+
     cur = tenant_conn.cursor()
     cur.execute(
         """
@@ -373,6 +411,10 @@ def publish_items(
     if not svc:
         raise ValueError("MercadoLibre not configured")
 
+    shipping_check = check_meli_shipping_config(svc, cfg)
+    if not shipping_check["ok"]:
+        return {"success": [], "failed": [{"inventory_id": "config", "error": shipping_check["error"]}]}
+
     cur = tenant_conn.cursor()
 
     # Batch fetch inventory rows

pos/services/meli_service.py

@@ -183,6 +183,9 @@ class MeliService:
     def get_category_attributes(self, category_id: str) -> list:
         return self._request("GET", f"/categories/{category_id}/attributes")
 
+    def get_shipping_preferences(self, user_id: str) -> dict:
+        return self._request("GET", f"/users/{user_id}/shipping_preferences")
+
     # ─── Orders ──────────────────────────────────────────────────────────
 
     def get_orders(