remove dead Scrollable-era widgets + simulateScroll param

Three widgets under lib/src/terminal/src/ui/ and one TerminalView
parameter were leftovers from the era when TerminalView wrapped its
viewport in a real Scrollable. The Scrollable path was replaced with
PointerScrollEvent → PgUp/PgDown translation (alive, well-tested in
terminal_view_test.dart); these helpers stayed behind with tests but
zero production callers.

Drops:
- TerminalScrollGestureHandler (scroll_handler.dart, 100 LOC)
- InfiniteScrollView (infinite_scroll_view.dart, 117 LOC)
- KeyboardVisibilty (keyboard_visibility.dart, 59 LOC) — last
  production caller was removed in 048e835
- TerminalView.simulateScroll parameter — declared, never read
- The matching test groups + imports in ui_widget_test.dart
- The KeyboardVisibilty export from the terminal barrel

Net: -585 lines from lib/ + test/, no behavior change, and
infinite_scroll_view.dart stops being the 90%-coverage outlier we
were apologising for in the previous test sweep.

Same shape as T-93 (dead onTapUp wiring), T-95 (dead tertiary tap),
and 048e835 (dead scrollController plumbing). Public-or-tested
surface that no caller exercised.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

test/terminal/ui/ui_widget_test.dart

@@ -1,16 +1,9 @@
-/// Widget tests for `lib/src/terminal/src/ui/` widget-level helpers
-/// (CustomKeyboardListener, KeyboardVisibilty, InfiniteScrollView,
-/// TerminalScrollGestureHandler).
+/// Widget tests for `lib/src/terminal/src/ui/` widget-level helpers —
+/// just CustomKeyboardListener now; the other widgets in this folder
+/// either don't need a widget tree or were retired as dead surface.
 library;
 
-import 'package:clide/src/terminal/src/core/buffer/cell_offset.dart';
-import 'package:clide/src/terminal/src/core/mouse/mode.dart';
-import 'package:clide/src/terminal/src/terminal.dart';
-import 'package:clide/src/terminal/src/ui/infinite_scroll_view.dart';
 import 'package:clide/src/terminal/src/ui/keyboard_listener.dart';
-import 'package:clide/src/terminal/src/ui/keyboard_visibility.dart';
-import 'package:clide/src/terminal/src/ui/scroll_handler.dart';
-import 'package:flutter/gestures.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -96,294 +89,4 @@ void main() {
       expect(inserts, isEmpty);
     });
   });
-
-  group('KeyboardVisibilty', () {
-    testWidgets('fires onKeyboardShow when bottom inset goes positive, onKeyboardHide when it returns to 0', (tester) async {
-      var shows = 0;
-      var hides = 0;
-      await tester.pumpWidget(_host(
-        KeyboardVisibilty(
-          onKeyboardShow: () => shows++,
-          onKeyboardHide: () => hides++,
-          child: const ColoredBox(color: Color(0xFF000000), child: SizedBox.expand()),
-        ),
-      ));
-      await tester.pump();
-
-      // Simulate keyboard appearance.
-      tester.view.viewInsets = const FakeViewPadding(bottom: 200, left: 0, right: 0, top: 0);
-      tester.binding.handleMetricsChanged();
-      await tester.pump();
-      expect(shows, 1);
-      expect(hides, 0);
-
-      // Simulate keyboard dismissal.
-      tester.view.resetViewInsets();
-      tester.binding.handleMetricsChanged();
-      await tester.pump();
-      expect(hides, 1);
-    });
-
-    testWidgets('repeated metrics events with the same bottom inset fire callbacks only when the inset changes', (tester) async {
-      var shows = 0;
-      await tester.pumpWidget(_host(
-        KeyboardVisibilty(
-          onKeyboardShow: () => shows++,
-          child: const ColoredBox(color: Color(0xFF000000), child: SizedBox.expand()),
-        ),
-      ));
-      await tester.pump();
-
-      tester.view.viewInsets = const FakeViewPadding(bottom: 200, left: 0, right: 0, top: 0);
-      tester.binding.handleMetricsChanged();
-      await tester.pump();
-      // Fire metrics again with the same inset — should not trigger again.
-      tester.binding.handleMetricsChanged();
-      await tester.pump();
-      expect(shows, 1);
-      addTearDown(tester.view.resetViewInsets);
-    });
-  });
-
-  group('InfiniteScrollView', () {
-    testWidgets('reports a scroll offset to onScroll when the viewport position moves', (tester) async {
-      final offsets = <double>[];
-      await tester.pumpWidget(_host(
-        InfiniteScrollView(
-          onScroll: offsets.add,
-          child: const SizedBox(width: 400, height: 1000),
-        ),
-      ));
-      await tester.pump();
-
-      // Drive the underlying ViewportOffset by sending a scroll event into
-      // the Scrollable.
-      final scrollable = find.byType(Scrollable);
-      await tester.drag(scrollable, const Offset(0, -100));
-      await tester.pumpAndSettle();
-      expect(offsets, isNotEmpty);
-    });
-
-    testWidgets('updates render object when onScroll callback identity changes', (tester) async {
-      var firstCalls = 0;
-      var secondCalls = 0;
-      Widget build(void Function(double) cb) => _host(
-            InfiniteScrollView(
-              onScroll: cb,
-              child: const SizedBox(width: 400, height: 1000),
-            ),
-          );
-
-      await tester.pumpWidget(build((_) => firstCalls++));
-      await tester.pump();
-      await tester.drag(find.byType(Scrollable), const Offset(0, -50));
-      await tester.pumpAndSettle();
-      final firstCount = firstCalls;
-      expect(firstCount, isPositive);
-
-      // Swap callback identity — render object's onScroll setter must update.
-      await tester.pumpWidget(build((_) => secondCalls++));
-      await tester.pump();
-      await tester.drag(find.byType(Scrollable), const Offset(0, -50));
-      await tester.pumpAndSettle();
-      expect(secondCalls, isPositive);
-      expect(firstCalls, firstCount); // first stops firing after swap
-    });
-  });
-
-  group('TerminalScrollGestureHandler', () {
-    testWidgets('main-buffer mode passes through without intercepting scroll', (tester) async {
-      final terminal = Terminal(maxLines: 100);
-      final handlerCalls = <Offset>[];
-
-      await tester.pumpWidget(_host(
-        TerminalScrollGestureHandler(
-          terminal: terminal,
-          getCellOffset: (offset) {
-            handlerCalls.add(offset);
-            return const CellOffset(0, 0);
-          },
-          getLineHeight: () => 14.0,
-          child: const ColoredBox(color: Color(0xFF000000), child: SizedBox.expand()),
-        ),
-      ));
-      await tester.pump();
-      // Main-buffer mode → the handler returns the child directly, no
-      // Listener around it. Sending a scroll event reaches nothing.
-      final pos = tester.getCenter(find.byType(TerminalScrollGestureHandler));
-      final mouse = await tester.createGesture(kind: PointerDeviceKind.mouse);
-      await mouse.addPointer(location: pos);
-      await tester.sendEventToBinding(PointerScrollEvent(
-        position: pos,
-        scrollDelta: const Offset(0, 100),
-      ));
-      await tester.pump();
-      expect(handlerCalls, isEmpty);
-    });
-
-    testWidgets('alt-buffer mode intercepts scroll; falls back to keyInput when terminal does not handle the mouse event', (tester) async {
-      final outputs = <String>[];
-      final terminal = Terminal(maxLines: 100, onOutput: outputs.add);
-      terminal.useAltBuffer();
-      // No mouse mode set on the terminal — mouseInput will return false,
-      // so the simulateScroll fallback kicks in (sends arrow keys).
-
-      await tester.pumpWidget(_host(
-        TerminalScrollGestureHandler(
-          terminal: terminal,
-          getCellOffset: (_) => const CellOffset(0, 0),
-          getLineHeight: () => 14.0,
-          child: const ColoredBox(color: Color(0xFF000000), child: SizedBox.expand()),
-        ),
-      ));
-      await tester.pump();
-      // Confirm the Listener is in the tree (isAltBuffer recognised on
-      // initial build).
-      expect(find.byType(Listener), findsOneWidget);
-
-      final pos = tester.getCenter(find.byType(TerminalScrollGestureHandler));
-      final mouse = await tester.createGesture(kind: PointerDeviceKind.mouse);
-      await mouse.addPointer(location: pos);
-      await tester.sendEventToBinding(PointerScrollEvent(
-        position: pos,
-        scrollDelta: const Offset(0, 100),
-      ));
-      await tester.pump();
-      // Falls back to TerminalKey.arrowDown via simulateScroll path → emits
-      // an escape via the default keytab.
-      expect(outputs, isNotEmpty);
-    });
-
-    testWidgets('alt-buffer mode + active mouse mode forwards as a real mouse event (no key fallback)', (tester) async {
-      final outputs = <String>[];
-      final terminal = Terminal(maxLines: 100, onOutput: outputs.add);
-      terminal.useAltBuffer();
-      // Activate a mouse mode so terminal.mouseInput consumes wheel events.
-      terminal.setMouseMode(MouseMode.upDownScroll);
-
-      await tester.pumpWidget(_host(
-        TerminalScrollGestureHandler(
-          terminal: terminal,
-          getCellOffset: (_) => const CellOffset(0, 0),
-          getLineHeight: () => 14.0,
-          child: const ColoredBox(color: Color(0xFF000000), child: SizedBox.expand()),
-        ),
-      ));
-      await tester.pump();
-      final pos = tester.getCenter(find.byType(TerminalScrollGestureHandler));
-      final mouse = await tester.createGesture(kind: PointerDeviceKind.mouse);
-      await mouse.addPointer(location: pos);
-      await tester.sendEventToBinding(PointerScrollEvent(
-        position: pos,
-        scrollDelta: const Offset(0, 100),
-      ));
-      await tester.pump();
-      // Mouse-mode active → mouseInput consumes; output is the mouse-report
-      // escape, not a PgDown / arrow.
-      expect(outputs, isNotEmpty);
-    });
-
-    testWidgets('alt-buffer mode with simulateScroll=false drops scrolls when the terminal does not consume them', (tester) async {
-      final outputs = <String>[];
-      final terminal = Terminal(maxLines: 100, onOutput: outputs.add);
-      terminal.useAltBuffer();
-
-      await tester.pumpWidget(_host(
-        TerminalScrollGestureHandler(
-          terminal: terminal,
-          getCellOffset: (_) => const CellOffset(0, 0),
-          getLineHeight: () => 14.0,
-          simulateScroll: false,
-          child: const ColoredBox(color: Color(0xFF000000), child: SizedBox.expand()),
-        ),
-      ));
-      await tester.pump();
-      final pos = tester.getCenter(find.byType(TerminalScrollGestureHandler));
-      final mouse = await tester.createGesture(kind: PointerDeviceKind.mouse);
-      await mouse.addPointer(location: pos);
-      await tester.sendEventToBinding(PointerScrollEvent(
-        position: pos,
-        scrollDelta: const Offset(0, 100),
-      ));
-      await tester.pump();
-      // Terminal didn't consume + simulateScroll false → no output at all.
-      expect(outputs, isEmpty);
-    });
-
-    testWidgets('switching the terminal into alt buffer flips the handler from passthrough to intercepting', (tester) async {
-      final terminal = Terminal(maxLines: 100);
-      await tester.pumpWidget(_host(
-        TerminalScrollGestureHandler(
-          terminal: terminal,
-          getCellOffset: (_) => const CellOffset(0, 0),
-          getLineHeight: () => 14.0,
-          child: const ColoredBox(color: Color(0xFF000000), child: SizedBox.expand()),
-        ),
-      ));
-      await tester.pump();
-      // Initially main-buffer → no Listener wrapping.
-      expect(find.byType(Listener), findsNothing);
-
-      terminal.useAltBuffer();
-      terminal.write(''); // notifyListeners via parser.write
-      await tester.pump();
-      // Alt-buffer → Listener wraps the child.
-      expect(find.byType(Listener), findsOneWidget);
-    });
-
-    testWidgets('alt-buffer Listener tracks pointer-down location for scroll-event positioning', (tester) async {
-      // Covers the onPointerDown handler that captures _lastPointerPosition
-      // for use by the next scroll event.
-      final outputs = <String>[];
-      final terminal = Terminal(maxLines: 100, onOutput: outputs.add)..useAltBuffer();
-      final cellOffsets = <Offset>[];
-      await tester.pumpWidget(_host(
-        TerminalScrollGestureHandler(
-          terminal: terminal,
-          getCellOffset: (offset) {
-            cellOffsets.add(offset);
-            return const CellOffset(0, 0);
-          },
-          getLineHeight: () => 14.0,
-          child: const ColoredBox(
-            color: Color(0xFF000000),
-            child: SizedBox.expand(),
-          ),
-        ),
-      ));
-      await tester.pump();
-      final pos = tester.getCenter(find.byType(TerminalScrollGestureHandler));
-      // Press first — that triggers onPointerDown which records the
-      // position into _lastPointerPosition.
-      final mouse = await tester.startGesture(pos, kind: PointerDeviceKind.mouse);
-      // Now scroll — getCellOffset is called with _lastPointerPosition.
-      await tester.sendEventToBinding(PointerScrollEvent(
-        position: pos,
-        scrollDelta: const Offset(0, 100),
-      ));
-      await tester.pump();
-      await mouse.up();
-      await tester.pumpAndSettle();
-      expect(cellOffsets, isNotEmpty);
-    });
-
-    testWidgets('didUpdateWidget rebinds listeners when the terminal instance changes', (tester) async {
-      final t1 = Terminal(maxLines: 100);
-      final t2 = Terminal(maxLines: 100)..useAltBuffer();
-      Widget build(Terminal t) => _host(
-            TerminalScrollGestureHandler(
-              terminal: t,
-              getCellOffset: (_) => const CellOffset(0, 0),
-              getLineHeight: () => 14.0,
-              child: const ColoredBox(color: Color(0xFF000000), child: SizedBox.expand()),
-            ),
-          );
-      await tester.pumpWidget(build(t1));
-      await tester.pump();
-      await tester.pumpWidget(build(t2));
-      await tester.pump();
-      // The Listener should now be present because t2 is in alt-buffer.
-      expect(find.byType(Listener), findsOneWidget);
-    });
-  });
 }