Phase 5: Föderations-Endpunkte — Cards ist föderierter Peer

Endpoints (alle Pfade aus app-manifest.json):
- POST /api/v1/share/receive — User-JWT-Auth, ShareEnvelope-Strict-
  Validation (cross-user-forbidden), Recipient-Match, Type-Accept-
  Lookup über Manifest, Payload-Schema-Validation, Handler-Dispatch
- POST /api/v1/tools/:name — User-JWT, dispatch nach `cards.create`
  und `cards.search` mit Tool-Schemas aus @cards/domain
- GET /api/v1/search — User-JWT, ILIKE auf cards.fields jsonb +
  decks.name, baut SearchResultEnvelope für mana-search-Aggregator
- GET /api/v1/dsgvo/export?user_id=… — Service-Key, voll-Bundle aller
  Cards-Daten des Users (decks, cards, reviews, study_sessions, tags,
  media_refs, import_jobs)
- POST /api/v1/dsgvo/delete — Service-Key, kaskadiert via FK-Cascade
  decks → cards → reviews/media_refs/card_tags/tags/study_sessions
  plus separates Cleanup von import_jobs

Share-Handlers (apps/api/src/share-handlers/):
- create_card_from_quote (mana/quote → front=text, back=source)
- save_link_as_card (mana/url → front=title, back=url+description)
- create_card_from_text (mana/text → front=erste-zeile, back=rest)
Alle landen via ensureInboxDeck() in einem auto-erstellten "Inbox"-Deck
pro User, inklusive automatischer FSRS-Reviews-Init in Transaktion.

Lokales Protocol-Mirror in @cards/domain/src/protocol/ (envelope,
payloads, search): TEMPORARY-Markierung mit Swap-Plan auf
@mana/shared-share-protocol via Verdaccio sobald NPM_AUTH_TOKEN da ist.
Spec-strict — UUID für user_id, ULID für share_id, Crockford-Base32.

Service-Key-Middleware mit constant-time-Compare gegen
process.env.CARDS_DSGVO_SERVICE_KEY (Phase F-1: ersetzt durch
mana-auth.app_service_keys-Lookup).

Tests:
- 70 Vitest-Tests grün (27 cards-domain + 43 apps/api):
  - share.test.ts: Auth-Gate, Cross-User-Sperre, User-Mismatch (403),
    Wrong-Recipient (422), Unknown-Type (422), Invalid-Payload (422),
    Wrapped { envelope, delivery_token }-Body akzeptiert
  - tools.test.ts: Auth, Unknown-Tool (404), cards.create-Validation,
    cards.search-Envelope-Shape
  - search.test.ts: Auth, Missing-Query (422), Query-too-long (422),
    Envelope-Version 0.1 + envelope-Felder
  - dsgvo.test.ts: Service-Key-Gate (401), Missing-User-ID (400),
    Export-Bundle-Shape, Delete-Counts, Key-not-configured (500)
- pnpm run type-check ✅ 4/4 packages
- E2E-Smoke gegen Postgres: Quote-Share→Inbox-Deck→Karte→Search-Hit→
  DSGVO-Export+Delete-Roundtrip clean (alle 3 Tabellen 0 nach delete)

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

apps/api/src/middleware/service-key.ts

@@ -0,0 +1,41 @@
+import type { MiddlewareHandler } from 'hono';
+
+/**
+ * Service-Key-Middleware für DSGVO-Endpunkte und sonstige
+ * service-zu-service-Calls.
+ *
+ * Heute (Phase 5): vergleicht `X-Service-Key`-Header per
+ * constant-time-Compare gegen `process.env.CARDS_DSGVO_SERVICE_KEY`.
+ *
+ * Phase F-1: ersetzt durch Verifikation gegen mana-auth's
+ * `apps.app_service_keys` Tabelle (caller-App = `mana-admin`).
+ */
+
+function constantTimeEquals(a: string, b: string): boolean {
+	if (a.length !== b.length) return false;
+	let mismatch = 0;
+	for (let i = 0; i < a.length; i++) {
+		mismatch |= a.charCodeAt(i) ^ b.charCodeAt(i);
+	}
+	return mismatch === 0;
+}
+
+export function serviceKeyAuth(opts: { envVar: string }): MiddlewareHandler {
+	return async (c, next) => {
+		const expected = process.env[opts.envVar];
+		if (!expected) {
+			return c.json(
+				{
+					error: 'service_key_not_configured',
+					detail: `${opts.envVar} env-var is not set`,
+				},
+				500
+			);
+		}
+		const provided = c.req.header('X-Service-Key');
+		if (!provided || !constantTimeEquals(provided, expected)) {
+			return c.json({ error: 'service_key_invalid' }, 401);
+		}
+		await next();
+	};
+}