feat(sync): add order_total field to SQLite tracking

Parse order total from GoMag JSON, store in SQLite orders table,
and expose via sync run API. Enables total display in mobile flat rows.

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

api/app/database.py

@@ -103,7 +103,8 @@ CREATE TABLE IF NOT EXISTS orders (
     factura_total_fara_tva REAL,
     factura_total_tva     REAL,
     factura_total_cu_tva  REAL,
-    invoice_checked_at    TEXT
+    invoice_checked_at    TEXT,
+    order_total           REAL
 );
 CREATE INDEX IF NOT EXISTS idx_orders_status ON orders(status);
 CREATE INDEX IF NOT EXISTS idx_orders_date ON orders(order_date);
@@ -301,6 +302,7 @@ def init_sqlite():
             ("factura_total_tva", "REAL"),
             ("factura_total_cu_tva", "REAL"),
             ("invoice_checked_at", "TEXT"),
+            ("order_total", "REAL"),
         ]:
             if col not in order_cols:
                 conn.execute(f"ALTER TABLE orders ADD COLUMN {col} {typedef}")