Trim files

lib/controllers/key_controller.dart

@@ -0,0 +1,18 @@
+import "dart:io";
+
+import "package:dart_jsonwebtoken/dart_jsonwebtoken.dart";
+import "package:matrixoidc/controllers/settings_controller.dart";
+import "package:riverpod/riverpod.dart";
+
+class KeyController extends AsyncNotifier<SecretKey> {
+  @override
+  Future<SecretKey> build() async => SecretKey(
+    (await File.fromUri(
+      Uri.file(ref.read(SettingsController.provider)!.jwtSecretFile),
+    ).readAsString()).trim(),
+  );
+
+  static final provider = AsyncNotifierProvider<KeyController, SecretKey>(
+    KeyController.new,
+  );
+}