Fundament: atomare Mandanten-Transaktionen, iframe-Vorschau, Uploads bis 25 MB, DSGVO-Felder

- db.ts: tenantTransaction() – atomar auch bei RLS_ENFORCED=true (AsyncLocalStorage
  bindet Operationen an eine craftvia_app-Transaktion, Kontext einmal gesetzt,
  verschachtelte Aufrufe treten bei, fremder Mandant wird abgewiesen)
- services/context.ts: inTransaction(ctx, fn); imports/confirm.ts umgestellt
- next.config.ts: EMBEDDABLE_FILE_ROUTES mit frame-ancestors 'self'/SAMEORIGIN
  (PDF-Vorschau Prüfmaske), proxyClientMaxBodySize 26mb (Import bis 25 MB)
- test-rls-enforcement: RLS-URL-Default aus DATABASE_URL (Lane-DBs)
- dsgvo/pii-fields: 26 Personenreferenzen des Craftvia-Domänenmodells
- ARCHITEKTUR §4.8: Transaktions-, Header-, Upload-, Versions- und PII-Regeln
- Test test-tenant-transaction (Commit/Rollback/Fremdmandant/Verschachtelung),
  grün im Owner- und im RLS-Modus

Gate: tsc, lint, build, 31/31 Tests grün.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/server/db.ts

@@ -1,3 +1,4 @@
+import { AsyncLocalStorage } from "node:async_hooks";
 import { PrismaClient } from "@prisma/client";
 import { PrismaPg } from "@prisma/adapter-pg";
 
@@ -329,6 +330,11 @@ async function applyTenantGuard(
  * `app.tenant_id` transaktionslokal gesetzt wird (verworfen bei Commit/Rollback
  * → kein Leak über den Pool). Die Guard-Logik ist in beiden Pfaden identisch.
  */
+type TxClient = Parameters<Parameters<PrismaClient["$transaction"]>[0]>[0];
+
+/** Active tenant transaction for the current async call chain (RLS path only). */
+const tenantTx = new AsyncLocalStorage<{ tenantId: string; tx: TxClient }>();
+
 export function dbForTenant(tenantId: string) {
   if (!tenantId) throw new Error("dbForTenant: tenantId is required");
 
@@ -353,6 +359,26 @@ export function dbForTenant(tenantId: string) {
             );
           }
 
+          // Inside tenantTransaction(): run on the shared transaction (atomic, context set once).
+          const active = tenantTx.getStore();
+          if (active) {
+            if (active.tenantId !== tenantId) {
+              throw new Error("Tenant isolation violation: nested transaction for another tenant");
+            }
+            const txDelegate = (active.tx as unknown as Record<
+              string,
+              Record<string, (a: unknown) => Promise<unknown>>
+            >)[model.charAt(0).toLowerCase() + model.slice(1)];
+            return applyTenantGuard(
+              active.tx as unknown as DelegateSource,
+              tenantId,
+              model,
+              operation,
+              args,
+              (a) => txDelegate[operation](a),
+            );
+          }
+
           // RLS-Pfad: alles in EINER Transaktion des Basisclients, damit
           // Kontextsetzung und Ausführung garantiert auf derselben Connection
           // liegen. `tx` ist uneextendiert → keine Rekursion in die Extension.
@@ -381,3 +407,37 @@ export function dbForTenant(tenantId: string) {
 }
 
 export type TenantDb = ReturnType<typeof dbForTenant>;
+
+/**
+ * Run `fn` atomically for one tenant. ALWAYS use this (or `inTransaction` in services)
+ * instead of `db.$transaction(...)` for multi-step writes — atomic in both modes:
+ *  - Owner mode: interactive transaction of the guarded client (the extension applies to tx).
+ *  - RLS mode: one craftvia_app transaction with app.tenant_id set once; every operation of the
+ *    guarded client inside `fn` (same async call chain) runs on that transaction.
+ * Nested calls join the outer transaction.
+ */
+export async function tenantTransaction<T>(
+  db: TenantDb,
+  tenantId: string,
+  fn: (tx: TenantDb) => Promise<T>,
+  options?: { timeout?: number; maxWait?: number },
+): Promise<T> {
+  if (!RLS_ENFORCED) {
+    if (isTransactionClient(db)) return fn(db);
+    return db.$transaction((tx) => fn(tx as unknown as TenantDb), options) as Promise<T>;
+  }
+  const active = tenantTx.getStore();
+  if (active) {
+    if (active.tenantId !== tenantId) throw new Error("Tenant isolation violation: nested transaction for another tenant");
+    return fn(db);
+  }
+  return appBase!.$transaction(async (tx) => {
+    await tx.$executeRaw`SELECT set_config('app.tenant_id', ${tenantId}, true)`;
+    return tenantTx.run({ tenantId, tx }, () => fn(db));
+  }, options);
+}
+
+/** Interactive transaction clients have no $transaction method. */
+function isTransactionClient(db: TenantDb): boolean {
+  return typeof (db as unknown as { $transaction?: unknown }).$transaction !== "function";
+}

src/server/dsgvo/pii-fields.ts

@@ -20,4 +20,33 @@ export interface PiiReference {
 export const PII_REFERENCE_FIELDS: readonly PiiReference[] = [
   { model: "AuditLog", field: "actorId" },
   { model: "NotificationPreference", field: "userId" },
+  // ── Craftvia domain (0002_craftvia_domain) ──
+  { model: "Customer", field: "createdById" },
+  { model: "Team", field: "leaderUserId" },
+  { model: "TeamMember", field: "userId" },
+  { model: "WorkOrder", field: "createdById" },
+  { model: "WorkOrder", field: "teamLeadUserId" },
+  { model: "WorkOrderAssignee", field: "userId" },
+  { model: "WorkOrderStatusChange", field: "actorId" },
+  { model: "ChecklistItem", field: "checkedById" },
+  { model: "MaterialUsage", field: "recordedById" },
+  { model: "WorkSession", field: "userId" },
+  { model: "TimeEntry", field: "userId" },
+  { model: "TimeEntry", field: "correctedById" },
+  { model: "ActivityNote", field: "authorId" },
+  { model: "Document", field: "uploadedById" },
+  { model: "Photo", field: "takenById" },
+  { model: "VoiceNote", field: "recordedById" },
+  { model: "Report", field: "createdById" },
+  { model: "Report", field: "teamApprovedById" },
+  { model: "Report", field: "approvedById" },
+  { model: "Signature", field: "capturedById" },
+  { model: "ImportJob", field: "importedById" },
+  { model: "ImportJob", field: "confirmedById" },
+  { model: "Notification", field: "userId" },
+  { model: "SyncOperation", field: "userId" },
+  { model: "SyncOperation", field: "resolvedById" },
+  { model: "AiGeneration", field: "createdById" },
+  // Free-text person data of END CUSTOMERS (Customer/Contact/Site/Signature.signerName) is
+  // tenant business data under data processing — not part of the employee subject export.
 ];

src/server/services/context.ts

@@ -1,5 +1,5 @@
 import type { Session } from "next-auth";
-import type { TenantDb } from "@/server/db";
+import { tenantTransaction, type TenantDb } from "@/server/db";
 
 /**
  * Context passed to every domain service. Created by server actions (from moduleGuard)
@@ -23,6 +23,15 @@ export function ctxFromGuard(g: { session: Session; db: TenantDb; permissions: R
   };
 }
 
+/**
+ * Run a multi-step write atomically (ARCHITEKTUR §4.8). `fn` receives a ctx whose `db`
+ * is bound to the transaction; nested calls join the outer transaction.
+ * Never use `ctx.db.$transaction(...)` directly — it is not atomic with RLS_ENFORCED=true.
+ */
+export function inTransaction<T>(ctx: ServiceCtx, fn: (ctx: ServiceCtx) => Promise<T>): Promise<T> {
+  return tenantTransaction(ctx.db, ctx.tenantId, (tx) => fn({ ...ctx, db: tx }));
+}
+
 export function can(ctx: ServiceCtx, permission: string): boolean {
   return ctx.permissions.has(permission);
 }

src/server/services/imports/confirm.ts

@@ -1,8 +1,7 @@
 import type { Prisma } from "@prisma/client";
-import type { TenantDb } from "@/server/db";
 import { writeAuditLog } from "@/server/audit";
 import { nextNumber } from "@/server/services/numbering";
-import { assertCan, ServiceError, type ServiceCtx } from "@/server/services/context";
+import { assertCan, inTransaction, ServiceError, type ServiceCtx } from "@/server/services/context";
 import { readStoredExtraction } from "@/lib/imports/extraction";
 import { computeCorrections, reviewFormSchema, type ReviewForm } from "@/lib/imports/review";
 // TODO(L3→L2): replace with the L2 work order service after merge (same input type).
@@ -65,9 +64,8 @@ export async function confirmImport(ctx: ServiceCtx, importId: string, rawForm:
   const corrections = computeCorrections(stored.fields, form);
   const now = new Date();
 
-  const result = await ctx.db.$transaction(async (tx) => {
-    const db = tx as unknown as TenantDb;
-    const txCtx: ServiceCtx = { ...ctx, db };
+  const result = await inTransaction(ctx, async (txCtx) => {
+    const db = txCtx.db;
 
     const switched = await db.importJob.updateMany({
       where: { id: job.id, status: "review_required" },