feat(order-detail): show CODMAT for direct SKUs + mapping validations

- Enrich order detail items with NOM_ARTICOLE data for direct SKUs
  (SKU=CODMAT) that have no ARTICOLE_TERTI entry
- Validate CODMAT exists in nomenclator before saving mapping (400)
- Block redundant self-mapping when SKU is already direct CODMAT (409)
- Show "direct" badge in CODMAT column for direct SKUs
- Show info alert in quick map modal for direct SKUs
- Display backend validation errors inline in modal

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

api/app/routers/sync.py

@@ -317,6 +317,29 @@ def _get_articole_terti_for_skus(skus: set) -> dict:
     return result
 
 
+def _get_nom_articole_for_direct_skus(skus: set) -> dict:
+    """Query NOM_ARTICOLE for SKUs that exist directly as CODMAT (direct mapping)."""
+    from .. import database
+    result = {}
+    sku_list = list(skus)
+    conn = database.get_oracle_connection()
+    try:
+        with conn.cursor() as cur:
+            for i in range(0, len(sku_list), 500):
+                batch = sku_list[i:i+500]
+                placeholders = ",".join([f":s{j}" for j in range(len(batch))])
+                params = {f"s{j}": sku for j, sku in enumerate(batch)}
+                cur.execute(f"""
+                    SELECT codmat, denumire FROM NOM_ARTICOLE
+                    WHERE codmat IN ({placeholders}) AND sters = 0 AND inactiv = 0
+                """, params)
+                for row in cur:
+                    result[row[0]] = row[1] or ""
+    finally:
+        database.pool.release(conn)
+    return result
+
+
 @router.get("/api/sync/order/{order_number}")
 async def order_detail(order_number: str):
     """Get order detail with line items (R9), enriched with ARTICOLE_TERTI data."""
@@ -334,6 +357,23 @@ async def order_detail(order_number: str):
             if sku and sku in codmat_map:
                 item["codmat_details"] = codmat_map[sku]
 
+        # Enrich direct SKUs (SKU=CODMAT in NOM_ARTICOLE, no ARTICOLE_TERTI entry)
+        direct_skus = {item["sku"] for item in items
+                       if item.get("sku") and item.get("mapping_status") == "direct"
+                       and not item.get("codmat_details")}
+        if direct_skus:
+            nom_map = await asyncio.to_thread(_get_nom_articole_for_direct_skus, direct_skus)
+            for item in items:
+                sku = item.get("sku")
+                if sku and sku in nom_map and not item.get("codmat_details"):
+                    item["codmat_details"] = [{
+                        "codmat": sku,
+                        "cantitate_roa": 1,
+                        "procent_pret": 100,
+                        "denumire": nom_map[sku],
+                        "direct": True
+                    }]
+
     # Enrich with invoice data
     order = detail.get("order", {})
     if order.get("factura_numar") and order.get("factura_data"):