v0.5.11

Added

• Playground chat on every surface. A first-class way to talk to the FCM router
  without configuring a coding tool. Press ; in the TUI, click the "Playground"
  nav button in the web dashboard, or run free-coding-models --playground /
  free-coding-models playground to open the in-TUI chat. Streams responses
  token-by-token, shows the routed-via provider/model + latency + tokens on each
  assistant message, and surfaces a friendly error if the router is offline.
• Router pre-prompt (router.prePrompt). A new configurable first-class
  system message injected by the daemon on every /v1/chat/completions request
  it proxies. Default text introduces the assistant as "free-coding-models, the
  free coding-model routing agent" so every tool and every Playground reply is
  framed as the FCM router. Always prepended (user system messages can still
  override specific instructions). Disabled by setting enabled: false.
• GET /api/router/preprompt and PUT /api/router/preprompt on both the
  router daemon and the web server. Same-origin only for PUT, same CORS policy
  as the rest of the API. Persists to ~/.free-coding-models.json; the daemon
  picks up the new value on its 10s config-reload tick.
• /api/playground/chat proxy on the web server. Browser Playground never
  talks to the daemon directly (no CORS, no exposed provider keys). Streams SSE
  when the client asks for stream: true; returns the upstream JSON otherwise.
• fcm virtual model support clarified. GET /v1/models advertises fcm
  (the auto-router) and fcm:<set-name> per set, so the Playground model
  selector shows both options.
• --playground flag and playground subcommand for the TUI:
  free-coding-models --playground boots the TUI directly into the chat
  overlay. --help lists it under "Config Flags".
• Default pre-prompt covers persona + dashboard pointer. When a user asks
  the model "which model served you?", the default persona tells them they
  were routed through the local FCM router and points them at the dashboard.
• 9 unit tests for pre-prompt injection (idempotence, no-mutation, disabled,
  empty, already-set, body-merge, garbage input, length cap, default text).
• 4 unit tests for playground error extraction so the OpenAI wire-format
  { error: { message, type, code } } is unwrapped into a string before
  React renders it (the bug a beta tester hit when the router was down).
• Robust M4 server smoke test. The pre-existing test asserted the router
  was offline, which fails on developer machines with a real daemon running.
  Now it asserts the response shape and adds pre-prompt + playground-proxy
  round-trips to the smoke checks.

Changed

• M4 server smoke test no longer fails on local dev machines. The test
  previously required the router to be offline; that is no longer a precondition.
• M4 settings view is untouched but the pre-prompt edit panel will land in
  a follow-up. (The pre-prompt is already exposed through the daemon API and
  the Web Settings round-trip; only the textarea is missing from the UI.)

Notes

• The default pre-prompt is ~120 words in English, code-first, and
  references the local dashboard. Users can fully replace it from any
  surface; the text is stored verbatim in ~/.free-coding-models.json.
• Pre-prompt is never sent to telemetry and is not logged by the daemon.
• The Playground honors the configured pre-prompt and lets the user toggle it
  off per-session. When off, the request is sent as-is and the assistant
  reply will not be framed as the FCM router.