fix(voice): track OAuth login lifecycle and storage readiness

docs/CURRENT-STATE.md

@@ -3924,6 +3924,8 @@ and unreachable upstream (502/504) separately from road geometry.
   3. **Every count names its scope in words** — "42 in your window", "8 in view", "about 30 within 250 km of Austin" — never a bare number. `analyst_query` returns `scopeLabel` so this is mechanical. Two different numbers with named scopes are not a contradiction.
   4. **The loaded-data caveat is stated once when relevant**: counts cover loaded data, and the flights layer loads where you look (appended to `coverage.note` for radius/view scopes over viewport-loaded layers).
 - **Degradation**: API-key mode without `OPENAI_API_KEY` returns 503 as before. Selecting OAuth without a usable local ChatGPT/Codex sign-in starts the local `codex login` browser flow, polls for the resulting local token, and selects OAuth when sign-in completes. If the Codex login flow cannot start or does not complete, the rest of the app is unaffected.
+- **Login lifecycle and storage**: one pending Codex login is shared by the login and status routes. Process failure, success without readable credentials, and a two-minute timeout each report a clear failure; timeout and server shutdown cancel the owned process. The launcher resolves `CODEX_HOME` before changing directories and refuses a mismatched `CODEX_AUTH_JSON`. GEV reads file credentials only, never writes or refreshes them, and does not require the vendor refresh token. Expired access tokens report `CODEX_OAUTH_REAUTH_REQUIRED`. OAuth status and login routes also use the same-site request gate.
+- **Support boundary**: the local OAuth option is experimental. OpenAI's documented Sign in with ChatGPT plan-sharing inference endpoint is `/v1/responses`; support for third-party reuse of Codex credentials at `/v1/realtime/client_secrets` remains unconfirmed. Technical success does not establish a supported auth or billing contract.
 
 ### AI HUD Summary (June 2026)