feat(voice): add typed AI chat beside voice

Chat sits next to the mic in the command dock. Replies are silent and never
request the microphone; the first message connects with the selected provider
and runs the same map actions as voice through each provider's text API
(OpenAI OPENAI_CHAT_MODEL, Gemini GEMINI_CHAT_MODEL via generateContent, which
never starts Live). Only one mode runs at a time.

- Chat panel rendered by the voice control presenter: conversation, recent and
  quick-command suggestions, Up/Down history, attachments (map-layer
  references or small UTF-8 text files, sent only with the message)
- Chat and voice panels sit above the dock or dock into the right rail's
  column; minimized bars sit centred above the dock, and height animates on
  swaps
- A centred panel steps down to its bar for the Location and Visual Presets
  trays without moving focus, rests above an open tray, and docks right while
  expanded over one; it returns to the centre once the trays close
- Minimized voice previews the last sentence from each side; the empty Voice
  Preview suggests things to say
- Settings opened from chat keep chat's frame and show the shared AI provider
  and quick commands; voice Settings show Back to voice
- Closing chat ends a typed session; the voice panel's close turns voice off
- The dock widens its voice control for the chat button and restyles its
  wings, which show icons only at 900px and below; assistant panels share the
  left panels' glass, and Cyber keeps its own surfaces
- Server text-chat handlers with body, time and per-IP limits
  (GEV_RATELIMIT_*_CHAT_PER_MIN), documented in SECURITY.md; tests and all
  eleven locales

Co-authored-by: Darren Dignam <[email protected]>

.env.example

@@ -61,6 +61,12 @@ CESIUM_ION_TOKEN=
 # ChatGPT/Codex OAuth session; the browser still receives only a short-lived
 # Realtime client secret. Do not prefix with VITE_.
 OPENAI_API_KEY=
+# Typed chat uses Chat Completions, independently of the voice model. It always
+# bills OPENAI_API_KEY; GEV_PREFER_CODEX_OAUTH below applies to voice only.
+OPENAI_CHAT_MODEL=gpt-4.1-mini
+# Typed chat requests (/api/openai/chat) per IP per minute, separate from the
+# voice throttle; 0 disables it. Not a billing cap.
+# GEV_RATELIMIT_OPENAI_CHAT_PER_MIN=60   # the default
 # Optional: forbid API-key voice sessions. Select ChatGPT OAuth in Provider
 # Settings; missing or expired Codex sign-in then fails closed.
 # GEV_PREFER_CODEX_OAUTH=true
@@ -269,3 +275,8 @@ OVERPASS_UPSTREAMS=
 # frame-ancestors sources such as "https://example.com", or * for any page.
 # Unset, no page may frame it. Other pages of the app can never be framed.
 # GEV_EMBED_FRAME_ANCESTORS=
+
+# Gemini typed chat uses generateContent; voice continues to use Gemini Live.
+GEMINI_CHAT_MODEL=gemini-3.5-flash-lite
+# Typed chat requests (/api/gemini/chat) per IP per minute; 0 disables it.
+# GEV_RATELIMIT_GEMINI_CHAT_PER_MIN=60   # the default