fix: execute_query now handles positional tuple params directly

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/services/firebird_service.py

@@ -78,14 +78,15 @@ class FirebirdService:
         try:
             cur = self.conn.cursor()
             if params:
-                # fdb no soporta :name — convertir a positional ?
-                param_names = re.findall(r':([a-zA-Z_][a-zA-Z0-9_]*)', query)
-                if param_names:
+                if isinstance(params, (list, tuple)):
+                    # Parámetros posicionales directos (?)
+                    cur.execute(query, params)
+                else:
+                    # Parámetros nombrados (:name) → convertir a positional
+                    param_names = re.findall(r':([a-zA-Z_][a-zA-Z0-9_]*)', query)
                     positional_sql = re.sub(r':[a-zA-Z_][a-zA-Z0-9_]*', '?', query)
                     positional_vals = [params[n] for n in param_names]
                     cur.execute(positional_sql, positional_vals)
-                else:
-                    cur.execute(query)
             else:
                 cur.execute(query)
             columns = [desc[0] for desc in cur.description] if cur.description else []