Adds a minimal Svelte 5 i18n primitive (`src/lib/i18n/`) backing the
login form, the layout blocker page, and the lobby placeholder.
SUPPORTED_LOCALES drives both the picker and the runtime lookup;
adding a language is a two-step change inside `src/lib/i18n/`.
Login form gains a globe-icon language dropdown (English / Русский
in their native names), defaulting to navigator.languages with `en`
as the fallback. Switching the locale re-renders the form in place;
on submit, the locale rides in the JSON body of `send-email-code`
because Safari/WebKit silently drops JS-set Accept-Language. Gateway
gains a body `locale` field that takes priority over the request
header for preferred-language resolution.
Email and code inputs disable browser autofill / suggestions
(`autocomplete=off` + `autocorrect=off` + `autocapitalize=off` +
`spellcheck=false`) so Keychain / address-book pickers and
remembered-value dropdowns no longer fire on focus.
Cross-cuts:
- backend & gateway openapi: clarify that body `locale` is honored.
- docs/FUNCTIONAL{,_ru}.md §1.2: document body-vs-header priority.
- gateway tests: body `locale` overrides Accept-Language; blank
body `locale` falls back to header.
- new ui/docs/i18n.md; cross-links from auth-flow.md and ui/README.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
TestServiceStartGameEndToEnd's httptest server had no handler for
/healthz, the path engineclient.Healthz probes after a runtime
container starts. Without it the runtime never transitions out of
starting state and the test fails on its 5s deadline. Surfaced by
introducing CI that runs the backend service tests outside the
integration harness.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>