feat: full feature buildout — streaming, i18n, mastery map, admin, jobs

Progressive lesson streaming via onSegment callback (fixes SSE for non-English
users — locale was shadowed in lesson-reader useEffect). Adds: BullMQ workers,
Redis stream buffer, token budget enforcement, Langfuse tracing, golden-eval
runner, Playwright e2e scaffolding, lesson depth/locale/preferences schema,
mastery map UI, admin panel (blueprints/users/reports/quality/misconceptions),
image queries, source citations, view transitions, reading animations, i18n
(next-intl), PDF export, surprise endpoint, and 402 passing unit tests.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/api/mastery/__tests__/route.test.ts

@@ -17,7 +17,9 @@ const ENTRIES = [
   {
     conceptId: 'c1',
     conceptName: 'Closures',
+    blueprintId: 'bp1',
     blueprintTitle: 'JavaScript',
+    blueprintIntentKey: 'javascript',
     score: 0.8,
     lastSeen: NOW,
     nextReview: LATER,
@@ -25,7 +27,9 @@ const ENTRIES = [
   {
     conceptId: 'c2',
     conceptName: 'Promises',
+    blueprintId: 'bp1',
     blueprintTitle: 'JavaScript',
+    blueprintIntentKey: 'javascript',
     score: 0.45,
     lastSeen: NOW,
     nextReview: NOW,