feat: settings web UI (models / STT / TTS speed / language / LLM instructions)

Adds /settings (served by the bridge) to change the LLM model (from installed
Ollama models), Whisper model, TTS engine + MeloTTS speed, output language,
agentic max-turns, thinking mode, and free-form LLM instructions — live, with a
'apply' that restarts the bridge + TTS worker. Settings persist to the runtime
config JSON; engine reads output_language + llm_instructions and the TTS worker
reads melo_speed from it. Bridge port publishable for access.

docker-compose.yml

@@ -119,6 +119,9 @@ services:
       # Browser-control endpoint a remote bot posts to (real xdotool input runs
       # on THIS host). Published on the LAN for the browser-host layout.
       - "${CDP_PUBLISH_BIND:-127.0.0.1}:${BROWSER_CONTROL_PORT:-8777}:8777"  # control-server
+      # Settings UI + brain API (bridge). Reach it at http://localhost:8765/settings
+      # on the bot host. Requires BRIDGE_HOST=0.0.0.0 (set in .env) to forward.
+      - "${SETTINGS_PUBLISH_BIND:-127.0.0.1}:${BRIDGE_PORT:-8765}:8765"  # bridge / settings
       # The brain bridge is NOT published: it binds the container's loopback
       # (BRIDGE_HOST=127.0.0.1) and is only consumed by the bot in this same
       # container, so it needs no host port and stays unreachable off-container.