fix(pwa): keep bootstrap watchdog active on startup errors

Prevents failed app bootstrap from being marked as successful so the boot watchdog can continue recovery attempts instead of suppressing them.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/main.tsx

@@ -91,5 +91,5 @@ void bootstrap().catch((err) => {
   renderBootstrapError(
     'Die App konnte nicht gestartet werden. Bitte neu laden oder die App vollständig beenden und erneut öffnen.',
   )
-  window.__KDB_APP_BOOTSTRAPPED = true
+  window.__KDB_APP_BOOTSTRAPPED = false
 })