fix(security): tier-0 audit blockers (next CVE, role gate, perm traps, key validation, rate limits)

Closes the five highest-risk findings from
docs/audit-comprehensive-2026-05-05.md so the platform is not exposed
while the rest of the audit backlog (1 CRIT + 18 HIGH + 32 MED + 23 LOW)
is worked through:

* CVE-2025-29927 — bump next 15.1.0 → 15.2.9; nginx strips
  X-Middleware-Subrequest at the edge as defense-in-depth.
* Cross-tenant role escalation — POST/PATCH/DELETE on /admin/roles now
  require super-admin (was: any holder of admin.manage_users).  Adds
  shared `requireSuperAdmin(ctx)` helper.
* Silent-403 traps — `documents.edit` and `files.edit` keys added to
  RolePermissions; seeded role values updated; migration 0041 backfills
  the new keys on every existing roles+port_role_overrides JSONB.  File
  routes remap the dead `create` action to `upload` / `manage_folders`.
* Berth-PDF / brochure register endpoints — reject body.storageKey
  unless it matches the namespace the matching presign endpoint issued
  (prevents repointing a tenant's PDF at foreign-port bytes).
* Portal auth rate limits — sign-in 5/15min/(ip,email),
  forgot-password 3/hr/IP, activate/reset/set-password 10/hr/IP.  Adds
  `enforcePublicRateLimit()` for non-`withAuth` routes.

Test status unchanged: 1168/1168 vitest, tsc clean.

Refs: docs/audit-comprehensive-2026-05-05.md (CRITICAL, HIGH §§1–4)

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

src/app/api/v1/files/folders/[...path]/route.ts

@@ -20,7 +20,7 @@ function sanitizeFolderPath(raw: string): string {
 }
 
 export const PATCH = withAuth(
-  withPermission('files', 'edit', async (req, ctx, params) => {
+  withPermission('files', 'manage_folders', async (req, ctx, params) => {
     try {
       const pathSegments = params.path;
       const currentPath = Array.isArray(pathSegments)

src/app/api/v1/files/folders/route.ts

@@ -12,7 +12,7 @@ const createFolderSchema = z.object({
 });
 
 export const POST = withAuth(
-  withPermission('files', 'create', async (req, ctx) => {
+  withPermission('files', 'manage_folders', async (req, ctx) => {
     try {
       const body = await parseBody(req, createFolderSchema);
 

src/app/api/v1/files/upload/route.ts

@@ -6,7 +6,7 @@ import { uploadFile } from '@/lib/services/files';
 import { uploadFileSchema } from '@/lib/validators/files';
 
 export const POST = withAuth(
-  withPermission('files', 'create', async (req, ctx) => {
+  withPermission('files', 'upload', async (req, ctx) => {
     try {
       const formData = await req.formData();
       const file = formData.get('file') as File | null;