Add smart ACK provider for WeChat MP replies

Replace fixed ackText with a rule-based AckProvider that picks
response templates by message type and intent (translate, summary,
rewrite, poster, ppt, mindmap, code, search, schedule). Pure sync,
zero I/O, auto-falls back to config.ackText on any error.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

mindspace-assets.test.mjs

@@ -4,6 +4,7 @@ import os from 'node:os';
 import path from 'node:path';
 import test from 'node:test';
 import { createAssetService, validateUploadRequest } from './mindspace-assets.mjs';
+import { DEFAULT_MAX_FILE_BYTES } from './mindspace.mjs';
 
 function createMockPool(state) {
   return {
@@ -87,7 +88,7 @@ function createMockPool(state) {
             state.versions.push({
               id: params[0],
               asset_id: params[1],
-              storage_key: params[3],
+              storage_key: params[2],
               scan_status: params[8],
             });
             return [[]];
@@ -166,6 +167,23 @@ test('validateUploadRequest rejects traversal filenames', () => {
   );
 });
 
+test('validateUploadRequest allows 5MB uploads by default', () => {
+  assert.doesNotThrow(() =>
+    validateUploadRequest({
+      filename: 'handbook.pdf',
+      sizeBytes: DEFAULT_MAX_FILE_BYTES,
+    }),
+  );
+  assert.throws(
+    () =>
+      validateUploadRequest({
+        filename: 'handbook.pdf',
+        sizeBytes: DEFAULT_MAX_FILE_BYTES + 1,
+      }),
+    (error) => error.code === 'file_too_large',
+  );
+});
+
 test('completeUpload marks safe files ready and blocks script payloads', async () => {
   const storageRoot = await fs.mkdtemp(path.join(os.tmpdir(), 'mindspace-assets-'));
   const state = {
@@ -206,6 +224,57 @@ test('completeUpload marks safe files ready and blocks script payloads', async (
   assert.equal(asset.scanStatus, 'blocked');
 });
 
+test('completeUpload publishes public images to the public temp image library', async () => {
+  const storageRoot = await fs.mkdtemp(path.join(os.tmpdir(), 'mindspace-assets-'));
+  const h5Root = await fs.mkdtemp(path.join(os.tmpdir(), 'mindspace-h5-'));
+  const state = {
+    categories: [
+      { id: 'cat-public', user_id: 'user-1', space_id: 'space-1', category_code: 'public' },
+    ],
+    spaces: [
+      {
+        id: 'space-1',
+        user_id: 'user-1',
+        quota_bytes: 5 * 1024 * 1024,
+        used_bytes: 0,
+        reserved_bytes: 0,
+        status: 'active',
+      },
+    ],
+    uploads: [],
+    assets: [],
+    versions: [],
+  };
+  let nextId = 0;
+  const service = createAssetService(createMockPool(state), {
+    storageRoot,
+    h5Root,
+    idFactory: () => `id-${++nextId}`,
+  });
+  const png = Buffer.from(
+    'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAwMCAO+/p9sAAAAASUVORK5CYII=',
+    'base64',
+  );
+
+  const upload = await service.createUpload('user-1', {
+    categoryId: 'cat-public',
+    filename: 'look.png',
+    sizeBytes: png.length,
+  });
+  await service.writeUploadContent('user-1', upload.id, png);
+  const asset = await service.completeUpload('user-1', upload.id);
+
+  assert.equal(asset.status, 'ready');
+  assert.match(asset.publicUrl, /^https:\/\/g2\.tkmind\.cn\/MindSpace\/user-1\/public\/\.tmp-images\/id-2\.png$/);
+  assert.equal(state.versions[0].storage_key, 'users/user-1/public/.tmp-images/id-2.png');
+  await assert.doesNotReject(() =>
+    fs.stat(path.join(storageRoot, 'users/user-1/public/.tmp-images/id-2.png')),
+  );
+  await assert.doesNotReject(() =>
+    fs.stat(path.join(h5Root, 'MindSpace/user-1/public/.tmp-images/id-2.png')),
+  );
+});
+
 test('createUpload rejects another users category id', async () => {
   const state = {
     categories: [