fix: keep Pick.saveFile source-compatible with file_picker 12

CHANGELOG.md

@@ -19,6 +19,7 @@ All notable changes to this project will be documented in this file.
 
 ### Fixed
 
+- **`Pick.saveFile` is source-compatible with file_picker 12.** file_picker 12 made `FilePicker.saveFile`'s `fileName` and `bytes` parameters required and non-null, which broke the analyzer build (`argument_type_not_assignable`) under a fresh `flutter pub get` that resolved the newer file_picker. `Pick.saveFile` keeps its nullable facade surface but now guards both arguments before forwarding, so the call type-checks against file_picker 11 and 12 and a null argument fails with a clear `ArgumentError` instead of an unhelpful type error. Touches `lib/src/facades/pick.dart`.
 - **`Crypt` now accepts the `base64:` app key that `key:generate` produces.** `key:generate` writes `APP_KEY=base64:<base64 of 32 random bytes>`, but `EncryptionServiceProvider` required `app.key` to be a raw 32-character string and threw `App Key must be 32 characters for AES-256` on the generated key, so `Crypt.encrypt`/`decrypt` were unusable out of the box. Added `MagicEncrypter.fromAppKey(appKey)` which base64-decodes a `base64:`-prefixed key to its 32 bytes (and still accepts a raw 32-character key); `EncryptionServiceProvider` now binds through it. Touches `lib/src/encryption/magic_encrypter.dart`, `lib/src/encryption/encryption_service_provider.dart`; adds three `fromAppKey` cases to `test/encryption/magic_encrypter_test.dart`.
 - **`MagicStatefulView` now calls the controller's `onInit()` lifecycle hook.** `MagicStatefulViewState.initState` listened to the controller and called the VIEW's own `onInit()` hook, but never invoked the CONTROLLER's `onInit()`, despite the documented contract. A controller that bootstraps in `onInit` (initial data load, table creation, subscriptions) silently never ran it when backed by a `MagicStatefulView`, so the screen rendered against uninitialized state (e.g. a query against a table the controller's `onInit` was supposed to create). It now calls `_controller.onInit()` guarded by `MagicController.initialized`, so a `SimpleMagicController` that already initialized in its constructor is not double-initialized and a singleton controller reused across re-mounts initializes exactly once per lifetime. Touches `lib/src/ui/magic_view.dart`; adds `test/ui/magic_view_controller_oninit_test.dart`.
 - **Auth no longer warns on every boot of a fresh app.** `AuthServiceProvider.boot()` logged a `userFactory not registered` warning (blaming provider order) whenever no userFactory was set, even for apps with no stored session to restore. It now only warns when a stored session actually exists (`Auth.hasToken()`) but cannot be rebuilt; a fresh app or a logged-out user stays quiet (debug-level). The stored-session check is guarded so a misconfigured Auth (for example, no Vault registered) cannot crash boot from this warning-verbosity path. Touches `lib/src/auth/auth_service_provider.dart`; adds three cases to `test/auth/auth_test.dart`.

lib/src/facades/pick.dart

@@ -349,8 +349,8 @@ class Pick {
   ///
   /// **Parameters:**
   /// - [dialogTitle]: Title of the save dialog.
-  /// - [fileName]: Default file name.
-  /// - [bytes]: Optional bytes to write to the file.
+  /// - [fileName]: File name to save as. Required; throws [ArgumentError] if null.
+  /// - [bytes]: Bytes to write to the file. Required; throws [ArgumentError] if null.
   ///
   /// ```dart
   /// final savePath = await Pick.saveFile(
@@ -363,6 +363,13 @@ class Pick {
     String? fileName,
     Uint8List? bytes,
   }) async {
+    // file_picker 12 made fileName and bytes required and non-null on
+    // FilePicker.saveFile; guard here so the nullable facade surface stays
+    // source-compatible across file_picker 11 and 12 and fails with a clear
+    // error instead of an unhelpful type error.
+    if (fileName == null || bytes == null) {
+      throw ArgumentError('Pick.saveFile requires both fileName and bytes.');
+    }
     return FilePicker.saveFile(
       dialogTitle: dialogTitle,
       fileName: fileName,

test/facades/pick_test.dart

@@ -0,0 +1,23 @@
+import 'dart:typed_data';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:magic/src/facades/pick.dart';
+
+void main() {
+  group('Pick.saveFile null guard', () {
+    test('throws ArgumentError when fileName is null', () {
+      expect(
+        () => Pick.saveFile(bytes: Uint8List.fromList([1, 2, 3])),
+        throwsArgumentError,
+      );
+    });
+
+    test('throws ArgumentError when bytes is null', () {
+      expect(() => Pick.saveFile(fileName: 'report.pdf'), throwsArgumentError);
+    });
+
+    test('throws ArgumentError when both are null', () {
+      expect(() => Pick.saveFile(), throwsArgumentError);
+    });
+  });
+}