Add Windows runner files for high DPI support and console output

- Created runner.exe.manifest to enable DPI awareness and dark mode support.
- Implemented utility functions in utils.cpp and utils.h for console creation and command line argument handling.
- Developed Win32Window class in win32_window.cpp and win32_window.h to manage high DPI-aware windows, including theme updates and message handling.

lib/data/note_repository.dart

@@ -0,0 +1,80 @@
+import 'package:notas/data/app_database.dart';
+import 'package:notas/models/note.dart';
+
+class NoteRepository {
+  NoteRepository({AppDatabase? database}) : _database = database ?? _sharedDatabase;
+
+  static final AppDatabase _sharedDatabase = AppDatabase();
+
+  final AppDatabase _database;
+
+  Future<List<Note>> loadNotes() async {
+    return _loadNotesFromDatabase();
+  }
+
+  Future<Note> createNote(Note note) async {
+    final int id = await _database.insertNoteAtTop(
+      NotesCompanion.insert(
+        title: note.title,
+        body: note.body,
+        createdAt: note.createdAt,
+        updatedAt: note.updatedAt,
+        sortIndex: 0,
+      ),
+    );
+
+    return note.copyWith(id: id, index: 0);
+  }
+
+  Future<Note> updateNote(Note note) async {
+    final int noteId = note.id ?? (throw ArgumentError('Note id is required to update a note.'));
+
+    await _database.updateNoteRow(
+      DbNote(
+        id: noteId,
+        title: note.title,
+        body: note.body,
+        createdAt: note.createdAt,
+        updatedAt: note.updatedAt,
+        sortIndex: note.index,
+      ),
+    );
+
+    return note;
+  }
+
+  Future<void> deleteNote(Note note) async {
+    final int noteId = note.id ?? (throw ArgumentError('Note id is required to delete a note.'));
+
+    await _database.deleteNoteAndShift(
+      id: noteId,
+      removedIndex: note.index,
+    );
+  }
+
+  Future<void> moveNote(Note note, int newIndex) async {
+    final int noteId = note.id ?? (throw ArgumentError('Note id is required to reorder a note.'));
+
+    await _database.moveNote(
+      id: noteId,
+      oldIndex: note.index,
+      newIndex: newIndex,
+    );
+  }
+
+  Future<List<Note>> _loadNotesFromDatabase() async {
+    final List<DbNote> rows = await _database.getAllNotes();
+    return rows.map(_fromRow).toList();
+  }
+
+  Note _fromRow(DbNote row) {
+    return Note(
+      id: row.id,
+      title: row.title,
+      body: row.body,
+      createdAt: row.createdAt,
+      updatedAt: row.updatedAt,
+      index: row.sortIndex,
+    );
+  }
+}