fix(audit-tier-6): validation, perms, ops/infra, per-port webhook secret

Final audit polish — closes the remaining LOW + MED items the previous
tiers didn't reach:

* Validation hardening: me.preferences uses .strict() + 8KB cap
  instead of unbounded .passthrough(); files.uploadFile gains
  magic-byte verification (jpeg/png/gif/webp/pdf/doc/xlsx); OCR scan
  endpoint enforces 10MB cap + magic-byte check on receipt images;
  port logoUrl + me.avatarUrl reject javascript:/data: schemes via
  a shared httpUrl refinement.
* Permission gates: document-sends/{brochure,berth-pdf} now require
  email.send (was withAuth-only); document-sends/{preview,list} on
  email.view; ai/email-draft on email.send; documents/[id]/send
  uses send_for_signing (was create); expenses/export/parent-company
  flips from hard isSuperAdmin to expenses.export for parity;
  admin/users/options gated on reminders.assign_others (was withAuth).
* Envelope hygiene: auth/set-password switches the third {message}
  variant to errorResponse + {data: {email}}; ai/email-draft wraps
  jobId in {data: {jobId}}.
* UI polish: reports-list.handleDownload surfaces failures via
  toastError (was console-only).
* Ops/infra: pin pnpm@10.33.2 across all three Dockerfiles +
  packageManager field in package.json; Dockerfile.worker re-orders
  user creation BEFORE pnpm install so node_modules / .cache dirs
  are worker-owned (fixes tesseract.js + sharp EACCES at first PDF
  parse); add Redis-ping HEALTHCHECK to the worker container.
* Public health endpoint: returns full env+appUrl payload only when
  the caller presents X-Intake-Secret, otherwise a minimal {status}
  so generic uptime monitors still work but anonymous internet
  doesn't get deployment fingerprints.
* Per-port Documenso webhook secret: new system_settings key
  + listDocumensoWebhookSecrets() helper.  The webhook receiver
  iterates every configured per-port secret with timing-safe
  comparison + falls back to env, then forwards the resolved portId
  into handleDocumentExpired so two ports sharing a documensoId
  cannot cross-mutate.

Deferred (handled in dedicated follow-up PRs):
* Tier 5.1 — direct service tests for portal-auth / users /
  email-accounts / document-sends / sales-email-config.  MED, large
  test-writing scope.
* The {ok: true} → {data: null} envelope migration across
  alerts/expenses/admin-ocr-settings/storage routes.  Mechanical but
  needs coordinated client + test updates.
* CSP-nonce migration (drop unsafe-inline) — needs middleware-level
  nonce generation that the Next 15 router has to thread through.
* Idempotency-Key header on Documenso createDocument.  Requires
  schema column on documents to persist the key; deferred so it
  doesn't bundle a migration into this commit.
* The 16 better-auth user_id FKs — separate dedicated migration
  with care (some columns are NOT NULL today and cascade decisions
  matter).
* PermissionGate / Skeleton / EmptyState wraps across 5 admin lists
  (auditor-H §§36–37) and the residential-clients filter bar.

Test status: 1175/1175 vitest, tsc clean.

Refs: docs/audit-comprehensive-2026-05-05.md MED §§28,29,30 + LOW §§32–43
+ HIGH §9 (Documenso secrets follow-up).

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

src/app/api/webhooks/documenso/route.ts

@@ -3,6 +3,7 @@ import { createHash } from 'crypto';
 
 import { db } from '@/lib/db';
 import { verifyDocumensoSecret } from '@/lib/services/documenso-webhook';
+import { listDocumensoWebhookSecrets } from '@/lib/services/port-config';
 import {
   handleRecipientSigned,
   handleDocumentCompleted,
@@ -11,7 +12,6 @@ import {
   handleDocumentRejected,
   handleDocumentCancelled,
 } from '@/lib/services/documents.service';
-import { env } from '@/lib/env';
 import { logger } from '@/lib/logger';
 
 // BR-024: Dedup via signatureHash unique index on documentEvents
@@ -49,9 +49,22 @@ export async function POST(req: NextRequest): Promise<NextResponse> {
   }
 
   // Documenso v1.13 + 2.x send the secret in plaintext via X-Documenso-Secret.
+  // Resolve the matching port by trying each configured per-port secret
+  // (plus the global env fallback) with timing-safe comparison. The
+  // resolved portId, when non-null, is threaded into handleDocumentExpired
+  // so two ports sharing a documensoId can't cross-mutate (auditor-D §22).
   const providedSecret = req.headers.get('x-documenso-secret') ?? '';
-
-  if (!verifyDocumensoSecret(providedSecret, env.DOCUMENSO_WEBHOOK_SECRET)) {
+  const secrets = await listDocumensoWebhookSecrets();
+  let matchedPortId: string | null = null;
+  let matched = false;
+  for (const entry of secrets) {
+    if (verifyDocumensoSecret(providedSecret, entry.secret)) {
+      matched = true;
+      matchedPortId = entry.portId;
+      break;
+    }
+  }
+  if (!matched) {
     logger.warn({ providedLen: providedSecret.length }, 'Invalid Documenso webhook secret');
     return NextResponse.json({ ok: false, error: 'Invalid secret' }, { status: 200 });
   }
@@ -149,7 +162,12 @@ export async function POST(req: NextRequest): Promise<NextResponse> {
         break;
 
       case 'DOCUMENT_EXPIRED':
-        await handleDocumentExpired({ documentId: documensoId });
+        // Forward the matched portId so cross-port documenso-id reuse
+        // can't flip the wrong port's document.
+        await handleDocumentExpired({
+          documentId: documensoId,
+          ...(matchedPortId ? { portId: matchedPortId } : {}),
+        });
         break;
 
       default: