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

apps/api/src/services/dash.ts

@@ -1,5 +1,5 @@
 import { AppError, ErrorCodes } from '@api/utils/errors';
-import { env } from '@api/config/env';
+import { env } from '@cio/core/config/env';
 import {
   getCourseStats,
   getDashOrgStats,
@@ -9,7 +9,7 @@ import {
   getTotalCertificatesIssued
 } from '@cio/db/queries/dash';
 import { dashLoginActivityKey } from '@api/utils/redis/key-generators';
-import { logRedisUnavailableOnce, redis } from '@api/utils/redis/redis';
+import { logRedisUnavailableOnce, redis } from '@cio/core/utils/redis/redis';
 
 import { OrganisationAnalytics } from '@api/types';
 import { getOrgIdBySiteName } from '@cio/db/queries';