add a shit ton of feature for the custom srs

lib/src/services/deck_repository.dart

@@ -6,6 +6,8 @@ import 'package:sqflite/sqflite.dart';
 import '../models/kanji_item.dart';
 import '../api/wk_client.dart';
 
+import 'package:flutter_dotenv/flutter_dotenv.dart';
+
 class DeckRepository {
   Database? _db;
   String? _apiKey;
@@ -98,6 +100,12 @@ class DeckRepository {
   }
 
   Future<String?> loadApiKey() async {
+    final envApiKey = dotenv.env['WANIKANI_API_KEY'];
+    if (envApiKey != null && envApiKey.isNotEmpty) {
+      _apiKey = envApiKey;
+      return _apiKey;
+    }
+
     final db = await _openDb();
     final rows = await db.query(
       'settings',