feat: vue3 frontend scaffold + org tree + customer list + chat timeline

M5b viewing frontend for the yunke data-mirror, under yunkes/.

- Scaffold: Vite + Vue 3 + TS, with element-plus, @element-plus/icons-vue,
  pinia, vue-router@4, axios. Dev server on :5173 with /api and /api/media
  proxied to the FastAPI backend on :8000.
- API client (src/api/): axios instance (baseURL '/api') whose response
  interceptor unwraps the axios envelope; typed wrappers (getCustomers,
  getMessages, getDepartments, getStaff) returning Page<T> / arrays; types
  mirroring the backend *Out schemas (Message typed as a permissive superset
  so file_th_url/duration/transcription_text degrade gracefully today and
  light up once MessageOut exposes them).
- Layout: el-header top bar (title + channel switch) + el-aside department
  tree (built from the flat parent_id list via useOrgStore, with search
  filter) + el-main router-view.
- CustomerList (/customers): el-table with channel filter, department filter
  driven by the tree selection (route query), pagination, and row-click into
  the chat timeline (channel + owner_account_id + talker_id).
- ChatTimeline (/chat/:channel/:ownerId/:talkerId): asc-ordered message
  bubbles keyed by is_send (direction) and type (text/image/video/voice/file/
  divider/system/unknown); lands on the most-recent page and prepends older
  pages via load-more with scroll anchoring.
- Home '/' redirects to '/customers'.

npm run build (vue-tsc -b + vite build) is clean.

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

yunkes/tsconfig.node.json

@@ -0,0 +1,23 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.node.tsbuildinfo",
+    "target": "es2023",
+    "lib": ["ES2023"],
+    "types": ["node"],
+    "skipLibCheck": true,
+
+    /* Bundler mode */
+    "module": "nodenext",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+
+    /* Linting */
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "erasableSyntaxOnly": true,
+    "noFallthroughCasesInSwitch": true
+  },
+  "include": ["vite.config.ts"]
+}