Add form-fill UIWorker example

A ReplyToolMixin UIWorker that fills inputs (fills) and toggles checkboxes /
presses submit (click) by voice — the state-changing half of the standard
action set.

examples/multi-worker/ui-worker/form-fill/client/vite.config.js

@@ -0,0 +1,7 @@
+import { defineConfig } from "vite";
+
+export default defineConfig({
+  server: {
+    port: 5173,
+  },
+});