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/ui/package.json

@@ -68,6 +68,7 @@
     "d3-array": "^3.2.4",
     "d3-scale": "^4.0.2",
     "dompurify": "^3.3.0",
+    "hls.js": "^1.6.16",
     "katex": "^0.16.25",
     "lowlight": "^3.3.0",
     "plyr": "^3.7.8",
@@ -79,8 +80,8 @@
     "tiptap-extension-auto-joiner": "^0.1.3"
   },
   "peerDependencies": {
-    "bits-ui": "^2.14.4",
     "@lucide/svelte": "^0.545.0 || ^0.562.0",
+    "bits-ui": "^2.14.4",
     "svelte-inview": "^4.0.4",
     "svelte-motion": "^0.12.2"
   }