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/src/custom/org-landing-page/saas/hero.svelte

@@ -8,9 +8,10 @@
   interface Props {
     hero: OrgLandingPageProps['hero'];
     navigation: Snippet;
+    showActions?: boolean;
   }
 
-  let { hero, navigation }: Props = $props();
+  let { hero, navigation, showActions = true }: Props = $props();
 </script>
 
 <EditableLandingSection sectionKey="hero">
@@ -32,19 +33,21 @@
         {hero.subheading}
       </p>
 
-      <div class="ui:flex ui:items-center ui:justify-center ui:gap-2.5">
-        <Button
-          href={hero.primaryAction.href}
-          disabled={hero.primaryAction.disabled ?? false}
-          size="lg"
-          class="ui:rounded-full ui:px-6"
-        >
-          {hero.primaryAction.label}
-        </Button>
-        {#if hero.secondaryAction}
-          <SecondaryActionButton href={hero.secondaryAction.href} label={hero.secondaryAction.label} variant="saas" />
-        {/if}
-      </div>
+      {#if showActions}
+        <div class="ui:flex ui:items-center ui:justify-center ui:gap-2.5">
+          <Button
+            href={hero.primaryAction.href}
+            disabled={hero.primaryAction.disabled ?? false}
+            size="lg"
+            class="ui:rounded-full ui:px-6"
+          >
+            {hero.primaryAction.label}
+          </Button>
+          {#if hero.secondaryAction}
+            <SecondaryActionButton href={hero.secondaryAction.href} label={hero.secondaryAction.label} variant="saas" />
+          {/if}
+        </div>
+      {/if}
 
       {#if hero.image}
         <div class="ui:mt-16 ui:max-w-4xl ui:mx-auto">