fix(voice): address review of typed AI chat

Typed chat sessions no longer end on the voice inactivity timeout, and a
failed or stopped reply keeps the conversation: Stop cancels only the
reply in progress, and map actions that already ran stay in the model's
context. Each upstream request and map action gets its own deadline, old
tool results shrink instead of the history overflowing, and step limits,
a missing or rejected key, the OAuth lock and throttling each get their
own message.

- Server: OpenAI chat is off under GEV_PREFER_CODEX_OAUTH; chat throttles
  default to the provider's throttle; replies carry API_KEY_MISSING,
  API_KEY_REJECTED, CODEX_OAUTH_REQUIRED and RATE_LIMITED codes; upstream
  Retry-After passes through, and a rejected key (Gemini's invalid-key 400
  included) cools down for a minute
- Pinokio forwards the chat throttle settings
- UI: the reply reveal publishes only the message list; the border orbit
  runs only while busy; layers attach with a button or Enter; the log is
  aria-busy while a reply types out; auto-scroll respects a reader who
  scrolled up; Escape closes the attach menu; the chat gear says Settings;
  a note says chat bills the OpenAI key when voice uses ChatGPT sign-in
- Layout does less work while panel height animates; unused blurs removed
- Gemini voice start ends chat; the voice preview clears on every new
  session
- Tests for the route gates, client limits, attachments and the fixes

README.md

@@ -362,11 +362,11 @@ _Why cockpit mode exists: you're riding a real aircraft over real terrain — an
 
 ## 🎙️ Talk to It
 
-The standalone app offers **OpenAI** and **Gemini** in the GEV MIC provider chooser. OpenAI is the initial default; your choice is saved in this browser. To use Gemini, add `GEMINI_API_KEY` in Provider Settings or your local `.env` file, then select Gemini. `GEMINI_LIVE_MODEL` defaults to `gemini-3.8-live`. The permanent key stays on the local server, which issues a constrained, single-use session credential.
+The standalone app offers **OpenAI** and **Gemini** under **AI Provider** in Settings, one choice shared by voice and chat. OpenAI is the initial default; your choice is saved in this browser. To use Gemini, add `GEMINI_API_KEY` in Provider Settings or your local `.env` file, then select Gemini. `GEMINI_LIVE_MODEL` defaults to `gemini-3.8-live`. The permanent key stays on the local server, which issues a constrained, single-use session credential.
 
-Changing provider ends the current conversation. If voice is on, the new provider starts with the same open-mic or push-to-talk mode; a held Space key is not carried over. Gemini uses the same map actions and captions, but has no OpenAI cost meter or MINI tier. When Gemini reports that its session has expired, start voice again for a new conversation. The provider chooser does not change the OpenAI-backed AI HUD summary.
+Changing provider ends the current conversation. If voice is on, the new provider starts with the same open-mic or push-to-talk mode; a held Space key is not carried over. Gemini uses the same map actions and captions, but has no OpenAI cost meter or MINI tier. When Gemini reports that its session has expired, start voice again for a new conversation. The AI Provider setting does not change the OpenAI-backed AI HUD summary.
 
-Next to the mic, **CHAT** opens a typed chat with silent replies. It uses the selected provider and the same map actions, and never asks for the microphone. OpenAI chat needs an API key (`OPENAI_CHAT_MODEL`); Gemini chat uses a separate text model (`GEMINI_CHAT_MODEL`). Chat and voice panels sit above the dock or dock to the right.
+Next to the mic, **CHAT** opens a typed chat with silent replies. It uses the selected provider and the same map actions, and never asks for the microphone. OpenAI chat needs an API key (`OPENAI_CHAT_MODEL`), so it is off while `GEV_PREFER_CODEX_OAUTH` pins OpenAI to ChatGPT OAuth; Gemini chat uses a separate text model (`GEMINI_CHAT_MODEL`). Chat and voice panels share the left panels' glass surface and sit above the dock or dock to the right.
 
 > Voice can use an **OpenAI API key** or, on the same machine, an opt-in signed-in **ChatGPT/Codex OAuth** session. The API-key path remains the default. Selecting ChatGPT OAuth in Provider Settings reuses an existing local sign-in or starts the Codex browser sign-in flow and selects OAuth when it completes. The OpenAI key still drives the **AI HUD summary**: a terse, five-word intelligence-style readout of the current view that regenerates as you move.