feat: HLS streaming, transcripts, agent course generation & landing-page course previews (#663)

New features:
- HLS video encoding/streaming (hls routes, hls-encoder) and a media
  transcripts pipeline (transcripts route + media-transcript queries)
- AI assistant chat vs. run model: agent-course-generation worker/queue,
  run-monitor pane, chat-changes card, content ask-ai bar
- Per-theme course-page previews across org landing-page themes (bold,
  classic, corporate, editorial, etc.) with a shared course token/component set
- View-as-student mode and login-link / link-invite invite flows

Refactor:
- Extract packages/core consolidating config (env, storage, dashboard-url),
  services and utils previously duplicated under apps/api/src/config
- Remove legacy agent service modules (chat-tools, chat-context,
  context-window, document, fetch-url, lesson-content)
- Relax Cross-Origin-Resource-Policy to allow cross-origin media embedding
- Add format script to tenant-router so turbo run format covers it

packages/jobs/src/enqueue/agent-course-generation.ts

@@ -0,0 +1,25 @@
+import type { JobsOptions } from 'bullmq';
+
+import { JOB_NAMES, QUEUE_NAMES } from '../queues/names';
+import { QUEUE_DEFAULTS } from '../queues/defaults';
+import { getQueue } from '../queues/factories';
+import type { TAgentCourseGenerationPayload } from '../payloads/agent-course-generation';
+
+function toJobId(runId: string, attempt: number): string {
+  return `agent-course-generation-${runId}-${attempt}`;
+}
+
+export async function enqueueAgentCourseGenerationRun(
+  payload: TAgentCourseGenerationPayload,
+  options: { attempt: number } & JobsOptions
+): Promise<string | undefined> {
+  const { attempt, ...jobOptions } = options;
+
+  const job = await getQueue(QUEUE_NAMES.agentCourseGeneration).add(JOB_NAMES.agentCourseGeneration.run, payload, {
+    ...QUEUE_DEFAULTS[QUEUE_NAMES.agentCourseGeneration],
+    jobId: toJobId(payload.runId, attempt),
+    ...jobOptions
+  });
+
+  return job.id;
+}

packages/jobs/src/enqueue/index.ts

@@ -1,2 +1,3 @@
 export * from './media';
 export * from './emails';
+export * from './agent-course-generation';