feat: show chapter numbers

lib/src/model/study/study.dart

@@ -35,6 +35,26 @@ class Study with _$Study {
     required IList<String?> deviationComments,
   }) = _Study;
 
+  /// Returns the indexed name of a chapter given its [chapterId].
+  ///
+  /// The indexed name is a string that combines the chapter's index (1-based)
+  /// and its name, formatted as "index. name".
+  ///
+  /// Throws a [RangeError] if the chapter with the given [chapterId] is not found.
+  ///
+  /// Example:
+  /// ```dart
+  /// final chapterName = study.getChapterIndexedName(chapterId);
+  /// print(chapterName); // Output: "1. Chapter Name"
+  /// ```
+  ///
+  /// - Parameter chapterId: The ID of the chapter to find.
+  /// - Returns: A string representing the indexed name of the chapter.
+  String getChapterIndexedName(StudyChapterId chapterId) {
+    final index = chapters.indexWhere((c) => c.id == chapterId);
+    return '${index + 1}. ${chapters[index].name}';
+  }
+
   StudyChapterMeta get currentChapterMeta => chapters.firstWhere((c) => c.id == chapter.id);
 
   factory Study.fromServerJson(Map<String, Object?> json) {

lib/src/model/study/study_controller.dart

@@ -601,8 +601,7 @@ class StudyState with _$StudyState {
   bool get canGoNext => currentNode.children.isNotEmpty;
   bool get canGoBack => currentPath.size > UciPath.empty.size;
 
-  String get currentChapterTitle =>
-      study.chapters.firstWhere((chapter) => chapter.id == currentChapter.id).name;
+  String get currentChapterTitle => study.getChapterIndexedName(study.chapter.id);
   bool get hasNextChapter => study.chapter.id != study.chapters.last.id;
 
   bool get isAtEndOfChapter => isOnMainline && currentNode.children.isEmpty;

lib/src/view/study/study_bottom_bar.dart

@@ -289,7 +289,7 @@ class _StudyChaptersMenuState extends ConsumerState<_StudyChaptersMenu> {
         for (final chapter in state.study.chapters)
           PlatformListTile(
             key: chapter.id == state.currentChapter.id ? currentChapterKey : null,
-            title: Text(chapter.name, maxLines: 2),
+            title: Text(state.study.getChapterIndexedName(chapter.id), maxLines: 2),
             onTap: () {
               ref.read(studyControllerProvider(widget.id).notifier).goToChapter(chapter.id);
               Navigator.of(context).pop();

test/view/study/study_screen_test.dart

@@ -129,8 +129,8 @@ void main() {
       // Wait for study to load
       await tester.pumpAndSettle();
 
-      expect(find.text('Chapter 1'), findsOneWidget);
-      expect(find.text('Chapter 2'), findsNothing);
+      expect(find.text('1. Chapter 1'), findsOneWidget);
+      expect(find.text('2. Chapter 2'), findsNothing);
 
       expect(find.text('pgn 1'), findsOneWidget);
       expect(find.text('pgn 2'), findsNothing);
@@ -143,8 +143,8 @@ void main() {
       // Wait for next chapter to load (even though it shouldn't)
       await tester.pumpAndSettle();
 
-      expect(find.text('Chapter 1'), findsNothing);
-      expect(find.text('Chapter 2'), findsOneWidget);
+      expect(find.text('1. Chapter 1'), findsNothing);
+      expect(find.text('2. Chapter 2'), findsOneWidget);
 
       expect(find.text('pgn 1'), findsNothing);
       expect(find.text('pgn 2'), findsOneWidget);
@@ -155,20 +155,20 @@ void main() {
       await tester.pumpAndSettle();
 
       expect(
-        find.descendant(of: find.byType(Scrollable), matching: find.text('Chapter 1')),
+        find.descendant(of: find.byType(Scrollable), matching: find.text('1. Chapter 1')),
         findsOneWidget,
       );
       expect(
-        find.descendant(of: find.byType(Scrollable), matching: find.text('Chapter 2')),
+        find.descendant(of: find.byType(Scrollable), matching: find.text('2. Chapter 2')),
         findsOneWidget,
       );
 
-      await tester.tap(find.text('Chapter 1'));
+      await tester.tap(find.text('1. Chapter 1'));
       // Wait for chapter to load
       await tester.pumpAndSettle();
 
-      expect(find.text('Chapter 1'), findsOneWidget);
-      expect(find.text('Chapter 2'), findsNothing);
+      expect(find.text('1. Chapter 1'), findsOneWidget);
+      expect(find.text('2. Chapter 2'), findsNothing);
 
       expect(find.text('pgn 1'), findsOneWidget);
       expect(find.text('pgn 2'), findsNothing);