Add hello-snapshot UIWorker example

Smallest UIWorker demo: a voice LLM in the main pipeline delegates
screen-relevant utterances to a UIWorker via a respond job; the UIWorker
auto-injects the current <ui_state> and answers grounded in what's on screen.
Includes a vanilla-JS client that streams accessibility snapshots over RTVI.

examples/multi-worker/ui-worker/hello-snapshot/client/package.json

@@ -0,0 +1,18 @@
+{
+  "name": "hello-snapshot-client",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@pipecat-ai/client-js": "1.9.0",
+    "@pipecat-ai/small-webrtc-transport": "^1.10.2"
+  },
+  "devDependencies": {
+    "vite": "^8"
+  }
+}