added quotes export to file

frontend/lib/provider/quote_provider.dart

@@ -1,10 +1,12 @@
 // gets all quotes from the database and returns them in a list
 
+import 'package:path_provider/path_provider.dart';
 import 'package:flutter/material.dart';
 
 import 'package:frontend/model/quote.dart';
 import 'package:frontend/repository/quote_repository.dart';
 import 'dart:math';
+import 'dart:io';
 
 class QuoteProvider extends ChangeNotifier {
   List<Quote> _quotes = [];
@@ -149,4 +151,30 @@ class QuoteProvider extends ChangeNotifier {
     populateAuthors();
     notifyListeners();
   }
+
+
+  Future<Directory> _getSaveDirectory() async {
+    if (Platform.isWindows || Platform.isLinux || Platform.isMacOS) {
+      final path = Platform.isWindows
+          ? Platform.environment['USERPROFILE']
+          : Platform.environment['HOME'];
+
+      return Directory(path!);
+    }
+
+    // Mobile fallback
+    return await getApplicationDocumentsDirectory();
+  }
+
+  Future<void> exportQuotesToFile() async {
+    final dir = await _getSaveDirectory();
+
+    final datetime = DateTime.now().toUtc().toString()
+      .replaceAll(" ", "T")
+      .replaceAll(":", "-")
+      .replaceAll(RegExp(r"\..*"), "");
+
+    final file = File('${dir.path}/hlasky_$datetime.txt');
+    await file.writeAsString("${filteredQuotes.join("\n")}\n");
+  }
 }