feat(useragent): initial connection impl

useragent/lib/providers/connection/bootstrap_token.dart

@@ -0,0 +1,22 @@
+
+
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+part 'bootstrap_token.g.dart';
+
+@Riverpod(keepAlive: true)
+class BootstrapToken extends _$BootstrapToken {
+  String? build() {
+    return null;
+  }
+
+  void set(String token) {
+    state = token;
+  }
+
+  String? take() {
+    final token = state;
+    state = null;
+    return token;
+  }
+}