chore: bump version to 0.9.0

File variety (video/pdf/generic), user status with custom message,
auto online/offline, DND gate for ring + notifications, drag-drop +
paste upload, @mentions in groups, link previews, emoji picker,
crash recovery.

apps/desktop/src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "ChatApp",
-  "version": "0.8.0",
+  "version": "0.9.0",
   "identifier": "com.meinname.chatapp",
   "build": {
     "beforeDevCommand": "pnpm vite:dev",