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.tokens.ts

@@ -0,0 +1,31 @@
+import type { OrgLandingPageTheme } from './types';
+import type { CourseLandingTokens } from './course-tokens-base';
+import { courseTokens as minimalTokens } from './minimal/course-tokens';
+import { courseTokens as boldTokens } from './bold/course-tokens';
+import { courseTokens as classicTokens } from './classic/course-tokens';
+import { courseTokens as saasTokens } from './saas/course-tokens';
+import { courseTokens as techTokens } from './tech/course-tokens';
+import { courseTokens as studioTokens } from './studio/course-tokens';
+import { courseTokens as corporateTokens } from './corporate/course-tokens';
+import { courseTokens as terminalTokens } from './terminal/course-tokens';
+import { courseTokens as editorialTokens } from './editorial/course-tokens';
+import { courseTokens as vibrantTokens } from './vibrant/course-tokens';
+
+export type { CourseLandingTokens } from './course-tokens-base';
+
+const TOKENS: Record<OrgLandingPageTheme, CourseLandingTokens> = {
+  minimal: minimalTokens,
+  bold: boldTokens,
+  classic: classicTokens,
+  saas: saasTokens,
+  tech: techTokens,
+  studio: studioTokens,
+  corporate: corporateTokens,
+  terminal: terminalTokens,
+  editorial: editorialTokens,
+  vibrant: vibrantTokens
+};
+
+export function courseLandingTokens(theme: OrgLandingPageTheme): CourseLandingTokens {
+  return TOKENS[theme] ?? minimalTokens;
+}