perf: avoid duplicate bootstrap work on join

apps/chanora_flutter/lib/services/app_bootstrap.dart

@@ -1,6 +1,7 @@
-import 'dart:io' show File;
+import 'dart:io' show Directory, File;
 
 import 'package:connectivity_plus/connectivity_plus.dart';
+import 'package:flutter/foundation.dart' show visibleForTesting;
 import 'package:flutter/services.dart';
 import 'package:package_info_plus/package_info_plus.dart';
 import 'package:path_provider/path_provider.dart';
@@ -9,7 +10,19 @@ import '../src/rust/api.dart' as rust;
 
 const String appSemverBaseline = 'v0.1.0';
 const String _sileroVadAsset = 'assets/models/silero_vad.onnx';
-const String _tenVadAsset = 'assets/models/ten_vad.onnx';
+
+typedef StorageDirectoryProvider = Future<Directory> Function();
+typedef StorageInitializer = Future<void> Function(String dir);
+
+Future<void>? _storageInitFuture;
+Future<void>? _vadBootstrapFuture;
+StorageDirectoryProvider _storageDirectoryProvider =
+    getApplicationSupportDirectory;
+StorageInitializer _storageInitializer = _defaultStorageInitializer;
+
+Future<void> _defaultStorageInitializer(String dir) {
+  return rust.initStorage(dir: dir);
+}
 
 Future<File> _copyBundledAssetToDocuments({
   required String assetPath,
@@ -29,16 +42,28 @@ Future<File> _copyBundledAssetToDocuments({
 }
 
 Future<void> configureBundledVadModels() async {
+  final existing = _vadBootstrapFuture;
+  if (existing != null) {
+    await existing;
+    return;
+  }
+
+  final bootstrap = _configureBundledVadModelsImpl();
+  _vadBootstrapFuture = bootstrap;
+  try {
+    await bootstrap;
+  } catch (_) {
+    _vadBootstrapFuture = null;
+    rethrow;
+  }
+}
+
+Future<void> _configureBundledVadModelsImpl() async {
   final silero = await _copyBundledAssetToDocuments(
     assetPath: _sileroVadAsset,
     fileName: 'silero_vad.onnx',
   );
-  final ten = await _copyBundledAssetToDocuments(
-    assetPath: _tenVadAsset,
-    fileName: 'ten_vad.onnx',
-  );
   await rust.setVadModelPath(path: silero.path);
-  await rust.setTenVadModelPath(path: ten.path);
 }
 
 /// Resolve the human-readable app version displayed in About.
@@ -69,15 +94,45 @@ String appVersionFromBuildNumber({
 }
 
 Future<void> wireStorage() async {
+  final existing = _storageInitFuture;
+  if (existing != null) {
+    await existing;
+    return;
+  }
+
+  final initFuture = _wireStorageImpl();
+  _storageInitFuture = initFuture;
+  await initFuture;
+}
+
+Future<void> _wireStorageImpl() async {
+  var initialized = false;
   try {
-    final dir = await getApplicationSupportDirectory();
-    await rust.initStorage(dir: dir.path);
+    final dir = await _storageDirectoryProvider();
+    await _storageInitializer(dir.path);
+    initialized = true;
   } catch (_) {
     // Best-effort; missing storage just means no identity persistence
     // and no bookmark list this session.
+  } finally {
+    if (!initialized) {
+      _storageInitFuture = null;
+    }
   }
 }
 
+@visibleForTesting
+void debugResetStorageBootstrap({
+  StorageDirectoryProvider? storageDirectoryProvider,
+  StorageInitializer? storageInitializer,
+}) {
+  _storageInitFuture = null;
+  _vadBootstrapFuture = null;
+  _storageDirectoryProvider =
+      storageDirectoryProvider ?? getApplicationSupportDirectory;
+  _storageInitializer = storageInitializer ?? _defaultStorageInitializer;
+}
+
 rust.BridgeNetworkState _mapConnectivity(List<ConnectivityResult> results) {
   if (results.isEmpty) return rust.BridgeNetworkState.unknown;
   final allNone = results.every((r) => r == ConnectivityResult.none);