When NEXT_PUBLIC_WS_URL is not set, the WebSocket URL defaulted to
ws://localhost:8080/ws. This broke real-time features (chat streaming,
live updates, notifications) for self-hosted deployments accessed over
LAN — the browser tried connecting to localhost on the client machine
instead of the Docker host.
Now the web app derives the WebSocket URL from window.location, routing
through the existing Next.js /ws rewrite. This works for localhost, LAN,
and custom domain setups without any extra configuration.
Also adds NEXT_PUBLIC_WS_URL as a Docker build arg for explicit override,
and documents LAN access configuration in SELF_HOSTING_ADVANCED.md.
Closes#896
NEXT_PUBLIC_* env vars must be available at Next.js build time to be
inlined into the client bundle. Without this, the Google OAuth button
never renders in self-hosted Docker deployments even when the env var
is correctly set in .env.
