Show BanGUI app version in sidebar, fix version tooltips

- Inject __APP_VERSION__ at build time via vite.config.ts define (reads
  frontend/package.json#version); declare the global in vite-env.d.ts.
- Render 'BanGUI v{__APP_VERSION__}' in the sidebar footer (MainLayout)
  when expanded; hidden when collapsed.
- Rename fail2ban version tooltip to 'fail2ban daemon version' in
  ServerStatusBar so it is visually distinct from the app version.
- Sync frontend/package.json version (0.9.0 → 0.9.3) to match
  Docker/VERSION; update release.sh to keep them in sync on every bump.
- Add vitest define stub for __APP_VERSION__ so tests compile cleanly.
- Add ServerStatusBar and MainLayout test suites (10 new test cases).

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "bangui-frontend",
   "private": true,
-  "version": "0.9.0",
+  "version": "0.9.3",
   "description": "BanGUI frontend — fail2ban web management interface",
   "type": "module",
   "scripts": {