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/classic/org.svelte

@@ -0,0 +1,76 @@
+<script lang="ts">
+  import type { OrgLandingPageProps } from '../types';
+  import OrgLandingPageEmbed from '../embed.svelte';
+  import OrgLandingPageLinks from '../links.svelte';
+  import OrgLandingPageCallout from '../callout.svelte';
+  import OrgLandingPageFooter from '../landing-page-footer.svelte';
+  import ClassicNav from './nav.svelte';
+  import ClassicHero from './hero.svelte';
+  import ClassicCourseCard from './course-card.svelte';
+  import { Button } from '../../../base/button';
+  import { themeStyle } from '../theme-style';
+
+  let {
+    orgName,
+    logoUrl,
+    navItems,
+    authAction,
+    hero,
+    courses,
+    hasMoreCourses = false,
+    disableCourseLinks = false,
+    embed,
+    callout,
+    links,
+    footer,
+    labels
+  }: OrgLandingPageProps = $props();
+</script>
+
+<div
+  class="ui:min-h-screen ui:bg-[var(--landing-bg-section)] ui:text-[var(--landing-fg)] ui:font-sans"
+  style={themeStyle('classic')}
+>
+  <ClassicNav {orgName} {logoUrl} {navItems} {authAction} />
+
+  <main>
+    <ClassicHero {hero} />
+
+    <section class="ui:py-10 ui:px-6 ui:lg:px-8 ui:max-w-7xl ui:mx-auto">
+      <div class="ui:text-center ui:mb-8">
+        <h2 class="ui:text-3xl ui:font-bold ui:text-[var(--landing-fg)]">
+          {labels?.catalogHeading ?? 'Featured Programs'}
+        </h2>
+        <div class="ui:mt-6 ui:h-px ui:w-24 ui:bg-[var(--landing-border)] ui:mx-auto"></div>
+      </div>
+
+      <div class="ui:grid ui:grid-cols-1 ui:sm:grid-cols-2 ui:lg:grid-cols-3 ui:gap-8 ui:justify-items-center">
+        {#each courses as course, index (course.id)}
+          <ClassicCourseCard {course} {disableCourseLinks} {labels} />
+        {/each}
+      </div>
+
+      {#if hasMoreCourses}
+        <div class="ui:mt-12 ui:flex ui:justify-center">
+          <Button
+            href={disableCourseLinks ? undefined : '/courses'}
+            variant="outline"
+            size="lg"
+            class="ui:px-8"
+            disabled={disableCourseLinks}
+          >
+            {labels?.browseCoursesLabel ?? 'View more courses'}
+          </Button>
+        </div>
+      {/if}
+    </section>
+  </main>
+
+  <OrgLandingPageLinks {links} {labels} variant="classic" />
+
+  <OrgLandingPageEmbed {embed} {labels} variant="classic" />
+
+  <OrgLandingPageCallout {callout} {labels} variant="classic" />
+
+  <OrgLandingPageFooter {orgName} {logoUrl} {footer} variant="classic" />
+</div>