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/v1/me/route.ts

@@ -5,20 +5,33 @@ import { withAuth, type AuthContext } from '@/lib/api/helpers';
 import { parseBody } from '@/lib/api/route-helpers';
 import { db } from '@/lib/db';
 import { userProfiles } from '@/lib/db/schema';
-import { errorResponse, NotFoundError } from '@/lib/errors';
+import { errorResponse, NotFoundError, ValidationError } from '@/lib/errors';
 import { z } from 'zod';
 
 const updateProfileSchema = z.object({
   displayName: z.string().min(1).max(200).optional(),
   phone: z.string().nullable().optional(),
-  avatarUrl: z.string().url().nullable().optional(),
+  // Refuse `javascript:` / `data:` schemes — z.string().url() lets them
+  // through and `<a href={avatarUrl}>` would otherwise be a stored-XSS
+  // vector if any future renderer treated the value as a link.
+  avatarUrl: z
+    .string()
+    .url()
+    .refine((u) => /^https?:\/\//i.test(u), 'must be an http(s) URL')
+    .nullable()
+    .optional(),
+  // Strict allow-list — no `.passthrough()` here.  The previous schema let
+  // arbitrary client-supplied keys survive validation and persist into
+  // `userProfiles.preferences` JSONB unbounded; auditor-E3 §28 caught this.
+  // Add new keys here as the UI surfaces them rather than letting the
+  // client mint them at will.
   preferences: z
     .object({
       dark_mode: z.boolean().optional(),
       locale: z.string().optional(),
       timezone: z.string().optional(),
     })
-    .passthrough()
+    .strict()
     .optional(),
 });
 
@@ -49,10 +62,18 @@ export const PATCH = withAuth(async (req, ctx: AuthContext) => {
     if (body.phone !== undefined) updates.phone = body.phone;
     if (body.avatarUrl !== undefined) updates.avatarUrl = body.avatarUrl;
     if (body.preferences !== undefined) {
-      updates.preferences = {
+      const merged = {
         ...((profile.preferences as Record<string, unknown>) ?? {}),
         ...body.preferences,
       };
+      // Hard cap on the merged JSONB to defend against historical rows
+      // bloated by the previous .passthrough() schema. 8 KB is generous
+      // — current legitimate keys are 3 booleans/strings.
+      const serialized = JSON.stringify(merged);
+      if (Buffer.byteLength(serialized, 'utf8') > 8 * 1024) {
+        throw new ValidationError('preferences exceeds 8KB');
+      }
+      updates.preferences = merged;
     }
 
     const [updated] = await db