Datastar's NewSSE() flushes HTTP headers before SCS's session middleware
can attach the Set-Cookie header, so the session cookie never reaches the
browser after login/register/logout.
Convert login, register, and logout to standard HTML forms with HTTP
redirects, which lets SCS write cookies normally. Also fix return_url
capture on the login page (was never being stored in the session).
Add handler tests covering login, register, and logout flows.
- Add brotli compression (level 5) to long-lived SSE event streams
(HandleGameEvents, HandleSnakeEvents) to reduce wire payload
- Fix all errcheck violations with nolint annotations for best-effort calls
- Fix goimports: separate stdlib, third-party, and local import groups
- Fix staticcheck: add package comments, use tagged switch
- Zero lint issues remaining
Migrate from the via meta-framework to direct dependencies:
- chi for routing, templ for HTML templates, datastar for SSE/reactivity
- Feature-sliced architecture (features/{auth,lobby,c4game,snakegame}/)
- Shared layouts and components (features/common/)
- Handler factory pattern (HandleX(deps) http.HandlerFunc)
- Embedded NATS server (nats/), SCS sessions (sessions/), chi router wiring (router/)
- Move ChatMessage domain type from ui package to game package
- Remove old ui/ package (gomponents-based via/h views)
- Remove via dependency from go.mod entirely
