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/dashboard/src/lib/features/course/pages/settings.svelte

@@ -367,10 +367,10 @@
       <Field.Field>
         <div class="relative w-fit">
           <img
-            style="min-width:280px; min-height:200px"
+            style="min-width:320px; min-height:200px"
             alt="Course cover"
             src={$settings.logo ? $settings.logo : '/images/classroomio-course-img-template.jpg'}
-            class="relative mt-2 h-[200px] w-[280px] rounded-md md:mt-0"
+            class="relative mt-2 h-[200px] w-[320px] rounded-md md:mt-0"
           />
         </div>
       </Field.Field>