Simplify demo: remove topics UI, ID-only connections

- Remove topic selection and peer discovery UI
- Remove MethodSelector and TopicsList components
- Simplify ConnectionForm to just take a connection ID
- Update to use @xtr-dev/rondevu-client@0.3.2
- Demo version: 0.3.2

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rondevu-demo",
-  "version": "1.0.2",
+  "version": "0.3.2",
   "description": "Demo application for Rondevu peer signaling and discovery",
   "type": "module",
   "scripts": {
@@ -10,7 +10,7 @@
     "deploy": "npm run build && npx wrangler pages deploy dist --project-name=rondevu-demo"
   },
   "dependencies": {
-    "@xtr-dev/rondevu-client": "^0.3.1",
+    "@xtr-dev/rondevu-client": "^0.3.2",
     "@zxing/library": "^0.21.3",
     "qrcode": "^1.5.4",
     "react": "^18.2.0",