feat(legal): Consent-Datenmodell, Migration & Registrierungs-Zustimmung (v1.7.1)

Teil 2 des Compliance-Updates — revisionssichere Zustimmungsprotokollierung:

- Prisma: Modelle LegalDocument (versioniert, contentHash, isActive, unique[type,version])
  und LegalAcceptance (userId, organizationId?, documentType/-Version, contentHash, context,
  unique gegen Duplikate, User-Relation)
- migrate.js: idempotente Tabellen + Indizes + Seeding/Aktivierung der 5 Rechtsdokumente
  (eine aktive Version je Typ; contentHash aus bewusster Versionsangabe)
- src/lib/legal.ts: getActiveDocuments, getPendingAcceptances, recordAcceptances (skipDuplicates,
  nie überschreiben), Pflichtsets (alle: TERMS+PRIVACY; Org-Admin zusätzlich ORGANIZATION_DECLARATION)
- API: GET /api/legal/status (offene Zustimmungen), POST /api/legal/accept (erfassen, CSRF-Check)
- Registrierung: zwei getrennte, nicht vorausgewählte Zustimmungen (Nutzungsbedingungen akzeptieren
  + Datenschutz-Kenntnisnahme), serverseitig via zod erzwungen, Version protokolliert

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/api/legal/accept/route.ts

@@ -0,0 +1,51 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { getSession } from '@/lib/auth'
+import { recordAcceptances, getPendingAcceptances, type LegalAcceptanceContext, type LegalDocumentType } from '@/lib/legal'
+
+const VALID_TYPES: LegalDocumentType[] = ['TERMS', 'PRIVACY', 'ORGANIZATION_DECLARATION', 'RESPONSIBLE_USE', 'DATA_PROCESSING_AGREEMENT']
+const VALID_CONTEXTS: LegalAcceptanceContext[] = ['REGISTRATION', 'LOGIN_RECONSENT', 'ORGANIZATION_CREATION', 'ADMIN_ROLE_ACCEPTANCE', 'DONATION']
+
+// POST: erfasst Zustimmungen des angemeldeten Benutzers revisionssicher.
+// body: { types: LegalDocumentType[], context: LegalAcceptanceContext }
+export async function POST(req: NextRequest) {
+  try {
+    const user = await getSession()
+    if (!user) return NextResponse.json({ error: 'Nicht autorisiert' }, { status: 401 })
+
+    // CSRF-Schutz: nur same-origin JSON-Requests (Cookie ist sameSite=lax).
+    const contentType = req.headers.get('content-type') || ''
+    if (!contentType.includes('application/json')) {
+      return NextResponse.json({ error: 'Ungültiger Request' }, { status: 400 })
+    }
+
+    const body = await req.json().catch(() => ({}))
+    const types: LegalDocumentType[] = Array.isArray(body.types)
+      ? body.types.filter((t: any) => VALID_TYPES.includes(t))
+      : []
+    const context: LegalAcceptanceContext = VALID_CONTEXTS.includes(body.context) ? body.context : 'LOGIN_RECONSENT'
+
+    if (types.length === 0) {
+      return NextResponse.json({ error: 'Keine gültigen Dokumenttypen' }, { status: 400 })
+    }
+
+    // Organisationsbezogene Zustimmung (Org-Bestätigung) an den Tenant binden.
+    const orgBound = context === 'ORGANIZATION_CREATION' || context === 'ADMIN_ROLE_ACCEPTANCE' || types.includes('ORGANIZATION_DECLARATION')
+    const organizationId = orgBound ? (user.tenantId ?? null) : null
+
+    const count = await recordAcceptances({
+      userId: user.id,
+      organizationId,
+      context,
+      types,
+      locale: 'de-CH',
+    })
+
+    const isOrgAdmin = user.role === 'TENANT_ADMIN'
+    const pending = await getPendingAcceptances(user.id, isOrgAdmin)
+
+    return NextResponse.json({ success: true, recorded: count, needsAcceptance: pending.length > 0, pending })
+  } catch (error) {
+    console.error('Error recording legal acceptance:', error)
+    return NextResponse.json({ error: 'Serverfehler' }, { status: 500 })
+  }
+}