feat(learn): + opens a sheet as Claude's, Camera, Photos and Files, and what goes along in rounded rows

Following the developer's review of 3 Nov 2026 (ADR 0021, D67):

- + below the assistant's field, and below a conversation's follow-up,
  opens "Add to your question" as Claude's "Add to session": three big
  tiles side by side, Camera (where the device takes photos) and Photos
  for an assistant reading images, and Files; below them, in the field, a
  row leading to what goes along, showing how far the assistant looks and
  how many parts are chosen.
- Camera and Photos through image_picker (flutter.dev's own): the camera's
  own app and the system's photo picker, no permission asked on Android, a
  file dialog on the desktop, which has no Camera; photos made at most
  2048 pixels a side, read on the device like any file attached.
- What goes along is chosen in rounded rows, as Claude's Permission, in
  place of radio buttons and chips: how far it looks with a tick, private
  studysets with a switch, the parts each with a tick, a card's image with
  its thumbnail.

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

apps/learn/halkyon_learn_flutter/test/feature/assistant/conversation_test.dart

@@ -33,6 +33,7 @@ import '../../support/fake_asset_server_gateway.dart';
 import '../../support/fake_card_gateway.dart';
 import '../../support/fake_conversation_gateway.dart';
 import '../../support/fake_grammar_gateway.dart';
+import '../../support/fake_photo_picker.dart';
 import '../../support/fake_settings_gateway.dart';
 import '../../support/fake_studyset_gateway.dart';
 import '../../support/memory_asset_file_cache.dart';
@@ -117,6 +118,7 @@ void main() {
   late FakeSettingsGateway settings;
   late FakeLlmClient llm;
   late FakeFilePicker picker;
+  late FakePhotoPicker photos;
   late MemoryDeviceSettingsStore store;
   late List<Uri> searched;
   late FakeAssetGateway assetGateway;
@@ -143,6 +145,7 @@ void main() {
     settings = FakeSettingsGateway();
     llm = FakeLlmClient();
     picker = FakeFilePicker();
+    photos = FakePhotoPicker();
     searched = [];
     assetGateway = FakeAssetGateway();
     assetFiles = MemoryAssetFileCache();
@@ -204,6 +207,7 @@ void main() {
         grammarGateway: grammar,
         grammarLanguages: grammarLanguages,
         files: picker,
+        photos: photos,
       ),
       location: location,
     );
@@ -270,6 +274,22 @@ void main() {
     await closeContext(tester);
   }
 
+  /// Opens + (with [tooltip]) and chooses [tile] in its sheet.
+  Future<void> add(
+    WidgetTester tester,
+    String tile, {
+    String tooltip = 'Attach a photo or file',
+    Finder? within,
+  }) async {
+    final plus = find.byTooltip(tooltip);
+    await tester.tap(
+      within == null ? plus : find.descendant(of: within, matching: plus),
+    );
+    await tester.pumpAndSettle();
+    await tester.tap(find.text(tile));
+    await tester.pumpAndSettle();
+  }
+
   /// Opens the menu of who answers, below the field.
   Future<void> openPicker(WidgetTester tester) async {
     await tester.tap(find.byTooltip('Who answers'));
@@ -1207,6 +1227,17 @@ void main() {
 
       await tester.tap(find.byTooltip('Attach a photo or file'));
       await tester.pumpAndSettle();
+      // As Claude's sheet has them (the developer's review of 3 Nov 2026).
+      final tiles = [
+        for (final tile in ['Camera', 'Photos', 'Files'])
+          tester.getRect(find.text(tile)),
+      ];
+      expect(tiles[0].center.dy, tiles[1].center.dy);
+      expect(tiles[1].center.dy, tiles[2].center.dy);
+      expect(tiles[0].left, lessThan(tiles[1].left));
+      await tester.tap(find.text('Files'));
+      await tester.pumpAndSettle();
+      expect(find.text('Camera'), findsNothing, reason: 'the sheet closed');
 
       expect(picker.asked.single, containsAll(['png', 'pdf', 'md']));
       expect(find.text('notes.md'), findsOneWidget);
@@ -1225,8 +1256,7 @@ void main() {
       await tester.pump(const Duration(seconds: 6));
       await tester.pumpAndSettle();
       picker.nextMany = [(name: 'extra.txt', bytes: bytesOf('Not this.'))];
-      await tester.tap(find.byTooltip('Attach a photo or file'));
-      await tester.pumpAndSettle();
+      await add(tester, 'Files');
       await tester.tap(
         find.descendant(
           of: find.widgetWithText(InputChip, 'extra.txt'),
@@ -1259,6 +1289,44 @@ void main() {
       );
     });
 
+    testWidgets("+'s Camera takes a photo and Photos picks some, each "
+        'shown above the question; a desktop has no Camera; what goes '
+        "along is chosen from +'s sheet too", (tester) async {
+      assistants.offer = AssistantsOffer(assistants: [_seeing]);
+      await showApp(tester);
+      photos
+        ..taken = (name: 'taken.jpg', bytes: bytesOf('a board'))
+        ..picked = [
+          (name: 'one.jpg', bytes: bytesOf('one')),
+          (name: 'two.png', bytes: bytesOf('two')),
+        ];
+
+      await add(tester, 'Camera');
+      await add(tester, 'Photos');
+
+      expect(photos.asked, ['camera', 'photos']);
+      for (final name in ['taken.jpg', 'one.jpg', 'two.png']) {
+        expect(find.widgetWithText(InputChip, name), findsOneWidget);
+      }
+
+      await tester.tap(find.byTooltip('Attach a photo or file'));
+      await tester.pumpAndSettle();
+      await tester.tap(find.text('What goes along').last);
+      await tester.pumpAndSettle();
+      expect(find.text('How far it looks'), findsOneWidget);
+    });
+
+    testWidgets('a desktop offers no Camera', (tester) async {
+      assistants.offer = AssistantsOffer(assistants: [_seeing]);
+      photos.hasCamera = false;
+      await showApp(tester);
+      await tester.tap(find.byTooltip('Attach a photo or file'));
+      await tester.pumpAndSettle();
+      expect(find.text('Camera'), findsNothing);
+      expect(find.text('Photos'), findsOneWidget);
+      expect(find.text('Files'), findsOneWidget);
+    });
+
     testWidgets('an assistant reading no images is offered files alone, '
         'and says why a picture picked anyway stays behind', (tester) async {
       await showApp(tester);
@@ -1266,6 +1334,10 @@ void main() {
 
       await tester.tap(find.byTooltip('Attach a file'));
       await tester.pumpAndSettle();
+      expect(find.text('Camera'), findsNothing);
+      expect(find.text('Photos'), findsNothing);
+      await tester.tap(find.text('Files'));
+      await tester.pumpAndSettle();
 
       expect(picker.asked.single, isNot(contains('png')));
       expect(
@@ -1284,13 +1356,12 @@ void main() {
       await ask(tester, 'Why て-form?');
 
       picker.next = (name: 'lines.txt', bytes: bytesOf('One.\nTwo.'));
-      await tester.tap(
-        find.descendant(
-          of: find.byType(BottomSheet),
-          matching: find.byTooltip('Attach a file'),
-        ),
+      await add(
+        tester,
+        'Files',
+        tooltip: 'Attach a file',
+        within: find.byType(BottomSheet),
       );
-      await tester.pumpAndSettle();
       expect(find.widgetWithText(InputChip, 'lines.txt'), findsOneWidget);
       expect(
         find.descendant(