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/src/components/ServerStatusBar.tsx

@@ -109,7 +109,7 @@ export function ServerStatusBar(): React.JSX.Element {
       {/* Version                                                          */}
       {/* ---------------------------------------------------------------- */}
       {status?.version != null && (
-        <Tooltip content="fail2ban version" relationship="description">
+        <Tooltip content="fail2ban daemon version" relationship="description">
           <Text size={200} className={styles.statValue}>
             v{status.version}
           </Text>