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/vibrant/course.svelte

@@ -0,0 +1,64 @@
+<script lang="ts">
+  import type { CourseLandingPageProps } from '../types';
+  import VibrantNav from './nav.svelte';
+  import VibrantHero from './hero.svelte';
+  import OrgLandingPageFooter from '../landing-page-footer.svelte';
+  import CourseSocialProof from '../course-social-proof.svelte';
+  import CourseInfoBlocks from '../course-info-blocks.svelte';
+  import CourseCurriculum from '../course-curriculum.svelte';
+  import CourseChips from '../course-chips.svelte';
+  import CourseSectionNav from '../course-section-nav.svelte';
+  import CourseInstructor from '../course-instructor.svelte';
+  import CourseReviews from '../course-reviews.svelte';
+  import CoursePricing from '../course-pricing.svelte';
+  import { themeStyle } from '../theme-style';
+  import { alignHeroCtaWithPricing, buildCourseSectionNavItems } from '../course-landing-page.helpers';
+
+  let {
+    orgName,
+    logoUrl,
+    navItems,
+    authAction,
+    hero,
+    socialProof,
+    info,
+    curriculum,
+    chips,
+    instructor,
+    reviews,
+    pricing,
+    footer,
+    labels
+  }: CourseLandingPageProps = $props();
+
+  const heroProps = $derived(alignHeroCtaWithPricing(hero, pricing));
+  const sectionNavItems = $derived(
+    buildCourseSectionNavItems({ info, curriculum, chips, instructor, reviews }, labels)
+  );
+</script>
+
+<div
+  class="ui:min-h-screen ui:bg-[var(--landing-bg)] ui:text-[var(--landing-fg)] ui:font-sans"
+  style={themeStyle('vibrant')}
+>
+  <main>
+    <VibrantHero hero={heroProps}>
+      {#snippet navigation()}
+        <VibrantNav {orgName} {logoUrl} {navItems} {authAction} />
+      {/snippet}
+    </VibrantHero>
+
+    <CourseSectionNav variant="vibrant" items={sectionNavItems} {labels} />
+    <CourseSocialProof variant="vibrant" {socialProof} {labels} />
+    <CourseInfoBlocks variant="vibrant" {info} {labels} />
+    <CourseCurriculum variant="vibrant" {curriculum} {labels} />
+    {#if chips}
+      <CourseChips variant="vibrant" {chips} {labels} />
+    {/if}
+    <CourseInstructor variant="vibrant" {instructor} {labels} />
+    <CourseReviews variant="vibrant" {reviews} {labels} />
+    <CoursePricing variant="vibrant" {pricing} {labels} />
+  </main>
+
+  <OrgLandingPageFooter {orgName} {logoUrl} {footer} variant="vibrant" />
+</div>