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/course-landing-page.helpers.ts

@@ -0,0 +1,52 @@
+import type { CoursePricing, CourseLandingPageProps, CourseLandingPageLabels } from './types';
+
+export function alignHeroCtaWithPricing(
+  hero: CourseLandingPageProps['hero'],
+  pricing: CoursePricing
+): CourseLandingPageProps['hero'] {
+  return {
+    ...hero,
+    primaryAction: {
+      label: pricing.ctaLabel,
+      href: pricing.ctaHref ?? '#pricing',
+      disabled: hero.primaryAction.disabled
+    }
+  };
+}
+
+export interface SectionNavItem {
+  id: string;
+  label: string;
+}
+
+export function buildCourseSectionNavItems(
+  props: Pick<CourseLandingPageProps, 'info' | 'curriculum' | 'chips' | 'instructor' | 'reviews'>,
+  labels?: CourseLandingPageLabels
+): SectionNavItem[] {
+  const items: SectionNavItem[] = [];
+  const { info, curriculum, chips, reviews } = props;
+
+  const hasInfo = Boolean(info.requirements || info.description || info.goals || info.certificateUrl);
+  if (hasInfo) {
+    items.push({ id: 'course-info', label: labels?.navAboutLabel ?? 'About' });
+  }
+
+  if (curriculum.sections.length > 0) {
+    items.push({ id: 'curriculum', label: labels?.navCurriculumLabel ?? 'Modules' });
+  }
+
+  const hasChips = Boolean((chips?.skills?.length ?? 0) > 0 || (chips?.tools?.length ?? 0) > 0);
+  if (hasChips) {
+    items.push({ id: 'course-chips', label: labels?.navSkillsLabel ?? 'Skills' });
+  }
+
+  items.push({ id: 'instructor', label: labels?.navInstructorLabel ?? 'Instructor' });
+
+  if (reviews.items.length > 0) {
+    items.push({ id: 'reviews', label: labels?.navReviewsLabel ?? 'Reviews' });
+  }
+
+  items.push({ id: 'pricing', label: labels?.navPricingLabel ?? 'Pricing' });
+
+  return items;
+}