Add WebSocket path config for community MQTT

Path hardcoded to "/". Brokers like analyzer.montrealmesh.ca need
non-root path (e.g. /mqtt). Expose field in fanout config + UI.

app/fanout/community_mqtt.py

@@ -59,6 +59,7 @@ class CommunityMqttSettings(Protocol):
     community_mqtt_iata: str
     community_mqtt_email: str
     community_mqtt_token_audience: str
+    community_mqtt_websocket_path: str
 
 
 def _base64url_encode(data: bytes) -> str:
@@ -361,7 +362,8 @@ class CommunityMqttPublisher(BaseMqttPublisher):
             kwargs["username"] = s.community_mqtt_username or None
             kwargs["password"] = s.community_mqtt_password or None
         if transport == "websockets":
-            kwargs["websocket_path"] = "/"
+            ws_path = getattr(s, "community_mqtt_websocket_path", None)
+            kwargs["websocket_path"] = ws_path.strip() if ws_path and ws_path.strip() else "/"
         return kwargs
 
     def _on_connected(self, settings: object) -> tuple[str, str]:

app/fanout/mqtt_community.py

@@ -62,6 +62,7 @@ def _config_to_settings(config: dict) -> SimpleNamespace:
         community_mqtt_iata=config.get("iata", ""),
         community_mqtt_email=config.get("email", ""),
         community_mqtt_token_audience=config.get("token_audience", ""),
+        community_mqtt_websocket_path=config.get("websocket_path", "/"),
     )
 
 

frontend/src/components/settings/SettingsFanoutSection.tsx

@@ -1548,6 +1548,24 @@ function MqttCommunityConfigEditor({
         </div>
       </div>
 
+      {((config.transport as string) || DEFAULT_COMMUNITY_TRANSPORT) === 'websockets' && (
+        <div className="grid grid-cols-1 sm:grid-cols-2 gap-4">
+          <div className="space-y-2">
+            <Label htmlFor="fanout-comm-ws-path">WebSocket Path</Label>
+            <Input
+              id="fanout-comm-ws-path"
+              type="text"
+              placeholder="/"
+              value={(config.websocket_path as string | undefined) ?? ''}
+              onChange={(e) => onChange({ ...config, websocket_path: e.target.value })}
+            />
+            <p className="text-[0.8125rem] text-muted-foreground">
+              Defaults to <code>/</code> — use <code>/mqtt</code> for brokers that require a path
+            </p>
+          </div>
+        </div>
+      )}
+
       <p className="text-[0.8125rem] text-muted-foreground">
         LetsMesh uses <code>token</code> auth. MeshRank uses <code>none</code>.
       </p>

tests/test_community_mqtt.py

@@ -70,6 +70,7 @@ def _make_community_settings(**overrides) -> SimpleNamespace:
         "community_mqtt_iata": "",
         "community_mqtt_email": "",
         "community_mqtt_token_audience": "mqtt-us-v1.letsmesh.net",
+        "community_mqtt_websocket_path": "/",
     }
     defaults.update(overrides)
     return SimpleNamespace(**defaults)
@@ -738,6 +739,24 @@ class TestLwtAndStatusPublish:
         assert kwargs["tls_context"] is not None
         assert kwargs["username"] == f"v1_{pubkey_hex}"
 
+    def test_build_client_kwargs_custom_websocket_path(self):
+        pub = CommunityMqttPublisher()
+        private_key, public_key = _make_test_keys()
+        settings = _make_community_settings(
+            community_mqtt_iata="MTL",
+            community_mqtt_websocket_path="/mqtt",
+        )
+
+        with (
+            patch("app.keystore.get_private_key", return_value=private_key),
+            patch("app.keystore.get_public_key", return_value=public_key),
+            patch("app.radio.radio_manager") as mock_radio,
+        ):
+            mock_radio.meshcore = None
+            kwargs = pub._build_client_kwargs(settings)
+
+        assert kwargs["websocket_path"] == "/mqtt"
+
     def test_build_client_kwargs_supports_tcp_transport_and_custom_audience(self):
         pub = CommunityMqttPublisher()
         private_key, public_key = _make_test_keys()