fix(security,reliability): address code-review findings

HIGH
- async handlers: Express 4 does not catch rejected promises and Node 22
  exits on unhandled rejections — a malformed body ({} to /cropper/dequeue
  etc.) could hang a request or kill the process. Every cropper route is
  now wrapped (throw → 500 via next), request bodies are validated up
  front (400), and JSON.parse of queue items is guarded. Server-wide
  error middleware added, honouring err.status (413 for oversized bodies).
- error pages HTML-escape all interpolated values — the login failure page
  rendered upstream (portal) error text raw.

MEDIUM
- outbound calls carry AbortSignal timeouts (5s OpenFGA verify, 15s
  cropper upstreams) — a hung upstream can no longer pin a request.
- body limits scoped: /cropper gets 50mb (picture data URLs), everything
  else 1mb (previously 50mb globally, memory-DoS surface pre-auth).
- cropper save validates the client-supplied domain against the catalog;
  picture fetches validate the Minio object key (id-domains/ prefix, no ..).

LOW
- static assets served before the session middleware (no PocketBase load
  per asset); landing header builds DOM nodes with textContent instead of
  innerHTML; picture load checks upstream ok.

5 new tests (40 total) covering malformed bodies, malformed queue items,
unknown domains, object-key traversal, and error-page escaping.

tools/test/cropper.test.js

@@ -86,19 +86,21 @@ async function startFakeA2loft() {
 const fakeMinio = () => ({
   presignedGetObject: async (_bucket, name) => `https://storage.example/${name}`,
 });
-const fakeQueue = () => {
+const fakeQueue = (messageText) => {
   const calls = { getMessage: 0, deleteMessage: 0 };
   const item = {
     messageId: 'm-1',
     popReceipt: 'pop-1',
     dequeueCount: 1,
-    messageText: JSON.stringify({
-      upload_id: 'up-1',
-      file_name: 'id-domains/ucth/raw-pictures/x/img.jpg',
-      caption: '08068287222',
-      domain: 'ucth',
-      raw_file_id: 'raw-1',
-    }),
+    messageText:
+      messageText ??
+      JSON.stringify({
+        upload_id: 'up-1',
+        file_name: 'id-domains/ucth/raw-pictures/x/img.jpg',
+        caption: '08068287222',
+        domain: 'ucth',
+        raw_file_id: 'raw-1',
+      }),
   };
   return {
     calls,
@@ -155,7 +157,7 @@ async function startFakeNodered() {
   return { calls, server, stop: () => stopServer(server) };
 }
 
-async function boot({ cropAllowed = true, cropperClients } = {}) {
+async function boot({ cropAllowed = true, cropperClients, queue } = {}) {
   const portal = await startFakePortal({ cropAllowed });
   const a2loft = await startFakeA2loft();
   const removebg = await startFakeRemovebg();
@@ -182,7 +184,7 @@ async function boot({ cropAllowed = true, cropperClients } = {}) {
     fetch: testFetch,
     cropperClients: cropperClients !== undefined ? cropperClients : {
       minio: fakeMinio(),
-      queue: fakeQueue(),
+      queue: queue || fakeQueue(),
       noderedAuth: { username: 'nr', password: 'nr-secret' },
       carvekitKey: 'carve-key',
     },
@@ -418,3 +420,83 @@ test('baseUrl exposes the identity-prefixed a2loft base', async () => {
     await stop();
   }
 });
+
+
+test('malformed request bodies are rejected, never hang the request', async () => {
+  const { base, a2loft, stop } = await boot();
+  try {
+    const cookies = await login(base);
+    for (const path of ['/cropper/picture/review', '/cropper/dequeue', '/cropper/profile/picture?otp=1']) {
+      const res = await fetch(`${base}${path}`, {
+        method: 'POST',
+        headers: { cookie: cookies, 'content-type': 'application/json' },
+        body: JSON.stringify({}),
+      });
+      assert.equal(res.status, 400, `${path} → ${res.status}`);
+      const body = await res.json();
+      assert.equal(body.ok, false);
+    }
+    assert.equal(a2loft.calls.filter((c) => c.url.includes('/profile/picture')).length, 0);
+  } finally {
+    await stop();
+  }
+});
+
+test('a malformed queue item does not hang the request', async () => {
+  const { base, stop } = await boot({ queue: fakeQueue('not-json') });
+  try {
+    const cookies = await login(base);
+    const res = await fetch(`${base}/cropper/picture/next`, { headers: { cookie: cookies } });
+    assert.equal(res.status, 200);
+    const body = await res.json();
+    assert.equal(body.ok, false);
+    assert.match(body.message, /malformed/i);
+  } finally {
+    await stop();
+  }
+});
+
+test('save rejects an unknown domain without contacting a2loft', async () => {
+  const { base, a2loft, stop } = await boot();
+  try {
+    const cookies = await login(base);
+    const res = await fetch(`${base}/cropper/profile/picture?otp=778899`, {
+      method: 'POST',
+      headers: { cookie: cookies, 'content-type': 'application/json' },
+      body: JSON.stringify({
+        pictureDataUrl: 'data:image/jpeg;base64,QUJD',
+        phone: '08068287222',
+        message: {
+          pop_receipt: 'custom',
+          message_id: 'm-1',
+          message: { upload_id: 'up-1', domain: '../../admin', agentDeviceHash: 'a' },
+        },
+      }),
+    });
+    assert.equal(res.status, 400);
+    assert.equal(a2loft.calls.length, 0, 'a2loft never contacted');
+  } finally {
+    await stop();
+  }
+});
+
+test('picture fetches reject object keys outside the id-domains prefix', async () => {
+  const { base, stop } = await boot();
+  try {
+    const cookies = await login(base);
+    // encoded traversal survives as a single path segment; a plain ../ is
+    // normalised away by the HTTP client before the route ever sees it
+    const traversal = await fetch(`${base}/cropper/picture/..%2F..%2Fsecret`, { headers: { cookie: cookies } });
+    assert.equal(traversal.status, 400, `got ${traversal.status}`);
+    const escapeWithinPrefix = await fetch(`${base}/cropper/picture/id-domains_.._.._secret`, {
+      headers: { cookie: cookies },
+    });
+    assert.equal(escapeWithinPrefix.status, 400, `got ${escapeWithinPrefix.status}`);
+    const ok = await fetch(`${base}/cropper/picture/id-domains_ucth_raw-pictures_x_img.jpg`, {
+      headers: { cookie: cookies },
+    });
+    assert.equal(ok.status, 200);
+  } finally {
+    await stop();
+  }
+});