Add teacher microphone and per-question model selection

src/lib/coding-teacher.ts

@@ -1,5 +1,6 @@
 import { hostApiFetch, createHostEventSource, ensureHostApiToken } from './host-api';
 import type {
+  TeacherModelCatalog,
   TeacherAvailability,
   TeacherCheckInInput,
   TeacherCheckInResult,
@@ -24,6 +25,7 @@ export function legacyTopicBase(base: string, legacyFriend: boolean) {
   return legacyFriend ? base.replace(/agent-topics$/, 'friend-topics') : base;
 }
 export const teacherApi = {
+  models: (runtime: 'local' | 'yuxi') => hostApiFetch<TeacherModelCatalog>('/api/coding/teacher/models?runtime=' + runtime),
   legacyHistory: (projectId: string) => hostApiFetch<TeacherTopicList>(`/api/coding/projects/${encodeURIComponent(projectId)}/agent-history`),
   legacyRead: (projectId: string, item: TeacherTopicList['items'][number]) => hostApiFetch<TeacherTopic>(
     `/api/coding/projects/${encodeURIComponent(projectId)}/agent-history/${encodeURIComponent(item.id)}?source=${encodeURIComponent(item.legacySourceId ?? 'project')}&friend=${item.legacyRole === 'friend'}`),