Phase 3: Domain-Modell + Decks/Cards/Reviews-CRUD

Domain (@cards/domain):
- zod-Schemas SSOT für Deck, Card, Review, StudySession, FsrsSettings,
  Tools (cards.create + cards.search Input/Output)
- CardType-Discriminated-Union: MVP basic+basic-reverse, Future-Set
  (cloze, type-in, image-occlusion, audio, multiple-choice) für
  Schema-stable-Migration vorbereitet
- validateFieldsForType() Pure-Function pro CardType
- FSRS-Adapter über ts-fsrs v5.3.2: newReview, gradeReview,
  subIndexCount, toFsrsCard/fromFsrsCard ISO↔Date-Roundtrip
- Encryption-Hinweis: reviews bleiben PLAINTEXT (Scheduler quert
  täglich `due <= now`, siehe Lessons §3)

Drizzle-Schemas (apps/api/src/db/schema, alles in pgSchema('cards')):
- decks, cards, card_tags, reviews (PK card_id+sub_index), study_sessions,
  tags (deck-skopiert), media_refs (verweist auf mana-media), import_jobs
- _schema.ts-Pattern um Zirkular-Imports zu vermeiden (Lesson aus
  mana-share/-events während F-0)
- Hot-Path-Index reviews_user_due_idx für Scheduler-Queries

Routes (apps/api/src/routes):
- POST/GET/PATCH/DELETE /api/v1/decks (Deck-CRUD)
- POST/GET/PATCH/DELETE /api/v1/cards (Card-CRUD mit Auto-Reviews-Init:
  beim Card-Insert werden N Reviews via subIndexCount(type) angelegt,
  in einer Transaktion)
- GET /api/v1/reviews/due (Hot-Path, optional deck_id-Filter, Limit 500)
- POST /api/v1/reviews/:cardId/:subIndex/grade (FSRS-State-Transition,
  per-Deck FSRS-Settings)

Auth: Stub-Middleware liest X-User-Id-Header (Phase 2 ersetzt durch
@mana/shared-hono authMiddleware mit JWKS-Cache).

Tests (vitest, Hono app.request()):
- @cards/domain: fsrs.test.ts (newReview, gradeReview Roundtrip,
  Rating-Mapping), schemas.test.ts (zod-strict-Variants, Field-Type-
  Validation, hex-Color)
- apps/api: decks.test.ts + cards.test.ts + reviews.test.ts —
  Auth-Gate + Input-Validation. Volle DB-Integrationstests folgen mit
  pg-mem oder testcontainers in späterer Phase.

Cleanup: types.ts entfernt, zod-Schemas sind SSOT (z.infer für Types).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/api/src/middleware/auth.ts

@@ -0,0 +1,27 @@
+import type { Context, MiddlewareHandler } from 'hono';
+
+/**
+ * Auth-Middleware-Stub für Phase 3.
+ *
+ * Heute (Dev): liest `X-User-Id`-Header.
+ * Phase 2 (echt): validiert User-JWT gegen mana-auth JWKS und extrahiert
+ * `sub`-Claim als userId.
+ *
+ * Implementations-Notiz: Phase 2 schwenkt auf `@mana/shared-hono`'s
+ * `authMiddleware()` um, das den JWKS-Cache verwaltet.
+ */
+export type AuthVars = { userId: string };
+
+export const authMiddleware: MiddlewareHandler<{ Variables: AuthVars }> = async (c, next) => {
+	const userId = c.req.header('X-User-Id');
+	if (!userId) {
+		return c.json({ error: 'unauthenticated', detail: 'X-User-Id header missing (dev stub)' }, 401);
+	}
+	c.set('userId', userId);
+	await next();
+};
+
+/** Helper zum Auslesen des userId aus dem Context (typed). */
+export function getUserId(c: Context<{ Variables: AuthVars }>): string {
+	return c.get('userId');
+}