style: preserve compact })) closing style in websocket_handler

Use # fmt: off/on blocks to keep compact dict-closing style for
json.dumps({...})) calls while letting ruff format the rest.

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

Author: paddymul

buckaroo/server/websocket_handler.py

@@ -37,15 +37,13 @@ def on_message(self, message):
         try:
             msg = json.loads(message)
         except (json.JSONDecodeError, TypeError):
-            self.write_message(
-                json.dumps(
-                    {
-                        "type": "error",
-                        "error_code": "invalid_json",
-                        "message": "Invalid JSON",
-                    }
-                )
-            )
+            # fmt: off
+            self.write_message(json.dumps({
+                "type": "error",
+                "error_code": "invalid_json",
+                "message": "Invalid JSON",
+            }))
+            # fmt: on
             return
 
         msg_type = msg.get("type")
@@ -134,17 +132,15 @@ def _handle_infinite_request(self, payload_args):
         session = sessions.get(self.session_id)
 
         if not session or (session.df is None and session.ldf is None):
-            self.write_message(
-                json.dumps(
-                    {
-                        "type": "infinite_resp",
-                        "key": payload_args,
-                        "data": [],
-                        "length": 0,
-                        "error_info": "No data loaded for this session",
-                    }
-                )
-            )
+            # fmt: off
+            self.write_message(json.dumps({
+                "type": "infinite_resp",
+                "key": payload_args,
+                "data": [],
+                "length": 0,
+                "error_info": "No data loaded for this session",
+            }))
+            # fmt: on
             return
 
         try:
@@ -193,17 +189,15 @@ def _handle_infinite_request(self, payload_args):
         except Exception:
             tb = traceback.format_exc()
             log.error("infinite_request error session=%s: %s", self.session_id, tb)
-            self.write_message(
-                json.dumps(
-                    {
-                        "type": "infinite_resp",
-                        "key": payload_args,
-                        "data": [],
-                        "length": 0,
-                        "error_info": tb if _BUCKAROO_DEBUG else "Request failed",
-                    }
-                )
-            )
+            # fmt: off
+            self.write_message(json.dumps({
+                "type": "infinite_resp",
+                "key": payload_args,
+                "data": [],
+                "length": 0,
+                "error_info": tb if _BUCKAROO_DEBUG else "Request failed",
+            }))
+            # fmt: on
 
     def on_close(self):
         sessions = self.application.settings["sessions"]