🩹(backend) allow enforcing WSS protocol to resolve browser compatibility

The LiveKit API URL is necessary to interact with the API. It uses https
protocol.

Eplicit wss protocol is necessary in Websocket constructor for some
older browsers.

This resolves critical compatibility issues with legacy browsers
(notably Firefox <124, Chrome <125, Edge <125) that lack support
for HTTPS URLs in the WebSocket() constructor. Without explicit WSS
URLs, WebSocket signaling connections may fail, crash, or be blocked
entirely in these environments.

The setting is optional and defaults to the current behavior when
not specified, ensuring zero breaking changes for existing deployments.

src/helm/env.d/dev-keycloak/values.meet.yaml.gotmpl

@@ -49,6 +49,7 @@ backend:
     {{- end }}
     {{- end }}
     LIVEKIT_API_URL: https://livekit.127.0.0.1.nip.io/
+    LIVEKIT_FORCE_WSS_PROTOCOL: True
     LIVEKIT_ENABLE_FIREFOX_PROXY_WORKAROUND: True
     ALLOW_UNREGISTERED_ROOMS: False
     FRONTEND_SILENCE_LIVEKIT_DEBUG: False