fix(studyset): Progress is always one of a studyset's parts

Progress joined the switch only once the studyset's reviews were read
and showed something studied, so the switch grew from two parts to
three after a moment. It is now always there, saying there is nothing
learnt yet where nothing was studied, as in Vaia; the switch never
changes as a studyset opens.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MMm7usAo6q9ZZRoPkWjoxi
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/lib/src/feature/studyset/widget/studyset_parts.dart

@@ -516,8 +516,8 @@ class const BrowseCardsButton({
 }
 
 /// The studyset [studysetId]'s progress, with everything inside it: how much
-/// is learnt, what is due today, and how long it was studied this week.
-/// Shown once anything in it was studied.
+/// is learnt, what is due today, and how long it was studied this week;
+/// nothing yet where nothing was studied.
 class const ProgressPart({
   required final String studysetId,
   required final ScrollController scroll,

halkyon_learn_flutter/lib/src/feature/studyset/widget/studyset_screen.dart

@@ -687,13 +687,11 @@ class const _BibliographyButton({required final Studyset studyset})
 
 /// Which part of the studyset shows, as the switch above it and the content
 /// share it: whether that is settled yet, the parts there are, the one
-/// shown, whether anything was studied, each part's scrolling, and how to
-/// show another.
+/// shown, each part's scrolling, and how to show another.
 typedef _PartsView = ({
   bool settled,
   List<StudysetPart> parts,
   StudysetPart shown,
-  bool studied,
   Map<StudysetPart, ScrollController> scrolls,
   ValueChanged<StudysetPart> show,
 });
@@ -701,7 +699,8 @@ typedef _PartsView = ({
 /// The studyset's content in three parts, chosen with the switch in the
 /// header: Material (its flashcards, notes and files, a section each),
 /// Progress (how much is learnt, what is due, the study time this week;
-/// only once anything in it was studied) and Study plan (its learning
+/// always, nothing yet where nothing was studied, decided 2026-10-12, so the
+/// switch never changes as reviews are read) and Study plan (its learning
 /// paths, and what to do next). [builder] gets which shows.
 ///
 /// It opens on the part it was left on, on this device ([StudysetTabs],
@@ -830,24 +829,10 @@ class _PartsState() extends State<_Parts> {
                 (_) => _chooseOnOpening(context.read<PathListBloc>().state),
               );
             }
-            // Progress once anything in it was studied: a card, or a path
-            // finished.
-            final studied =
-                (context.watch<StudysetActivityCubit>().state?.studied ??
-                    false) ||
-                context.select<PathListBloc, bool>(
-                  (bloc) => bloc.state.completed.isNotEmpty,
-                );
-            final parts = [
-              StudysetPart.material,
-              if (studied) StudysetPart.progress,
-              StudysetPart.plan,
-            ];
             return widget.builder(context, (
               settled: _settled,
-              parts: parts,
-              shown: parts.contains(_part) ? _part : StudysetPart.material,
-              studied: studied,
+              parts: StudysetPart.values,
+              shown: _part,
               scrolls: _scrolls,
               show: _show,
             ));
@@ -879,13 +864,10 @@ class const _Content({
           scroll: parts.scrolls[StudysetPart.material]!,
           labelled: labelled,
         ),
-        if (parts.studied)
-          ProgressPart(
-            studysetId: studysetId,
-            scroll: parts.scrolls[StudysetPart.progress]!,
-          )
-        else
-          const SizedBox.shrink(),
+        ProgressPart(
+          studysetId: studysetId,
+          scroll: parts.scrolls[StudysetPart.progress]!,
+        ),
         PlanPart(
           studysetId: studysetId,
           scroll: parts.scrolls[StudysetPart.plan]!,

halkyon_learn_flutter/test/feature/studyset/widget/studyset_screen_test.dart

@@ -1682,15 +1682,18 @@ void main() {
     );
   });
 
-  testWidgets('Progress shows once a card in the studyset was studied: how '
-      'much is learnt, what is due, and the study time this week', (
-    tester,
-  ) async {
+  testWidgets('Progress is always there, nothing yet before anything is '
+      'studied; then how much is learnt, what is due, and the study time '
+      'this week', (tester) async {
     stored('japanese', 'Japanese');
     final id = await card('japanese', '猫');
     await showApp(tester, location: RoutePaths.studyset('japanese'));
     await tester.pumpAndSettle();
-    expect(parts(tester), ['Material', 'Study plan']);
+    expect(parts(tester), ['Material', 'Progress', 'Study plan']);
+    await openPart(tester, 'Progress');
+    expect(find.text('0 of 1 card'), findsOneWidget);
+    expect(find.text('0 min'), findsOneWidget);
+    await openPart(tester, 'Material');
 
     await PersonScope.of(
       tester.element(find.byType(StudysetScreen)),