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/utils/course-completion.ts

@@ -1,4 +1,4 @@
-import { getDashboardBaseUrl } from '@api/config/dashboard-url';
+import { getDashboardBaseUrl } from '@cio/core/config/dashboard-url';
 import {
   getCourseProgress as getCourseProgressQuery,
   type TCourseCertificationRow
@@ -67,7 +67,11 @@ export function scheduleCertificationCompletionWork(params: {
         return;
       }
 
-      const base = getDashboardBaseUrl(courseRow.orgSiteName ?? undefined);
+      const base = getDashboardBaseUrl({
+        siteName: courseRow.orgSiteName,
+        customDomain: courseRow.orgCustomDomain,
+        isCustomDomainVerified: courseRow.orgIsCustomDomainVerified
+      });
       const certificateUrl = `${base}/courses/${courseId}/certificates`;
 
       await enqueueTransactionalEmail('studentCourseCompletion', {