feat: add per-message model and reasoning effort override

Allow users to select a different model and reasoning effort level
directly from the chat input toolbar, overriding the bot defaults
on a per-message basis. The backend accepts optional model_id and
reasoning_effort parameters via both WebSocket and HTTP APIs, with
request-level values taking priority over bot/session settings.

- Backend: extend wsClientMessage and LocalChannelMessageRequest with
  model_id/reasoning_effort fields; add ReasoningEffort to ChatRequest;
  update resolver to prioritize request-level reasoning effort
- Frontend: add ModelOptions and ReasoningEffortSelect shared components;
  refactor model-select to reuse ModelOptions; add model/reasoning
  selectors to chat input toolbar; initialize from bot settings
- Regenerate swagger spec and TypeScript SDK

spec/swagger.yaml

@@ -1375,6 +1375,10 @@ definitions:
     properties:
       message:
         $ref: '#/definitions/channel.Message'
+      model_id:
+        type: string
+      reasoning_effort:
+        type: string
     type: object
   handlers.LoginRequest:
     properties: