wire the output dock into the layout — toggle, tabs, persistence (T-54)

The D-87 bottom dock, end to end. New Slots.dock in the classic preset
(hidden by default); RootLayout renders it full-width above the status bar
when open, capped at half the window so Claude stays largest (the D-47
amendment). LogRing now lives on KernelServices (boot tees the kernel logger
into it; main.dart also tees the IPC/MCP logger), so the dock shows logs from
every subsystem.

OutputExtension contributes the Output tab, the merged health/toggle
status-bar widget (green check when clean, warn/error counts otherwise) that
replaces the old ipc-status item, and the dock.toggle command (Ctrl+J).
Problems moves out of the sidebar into the dock. open/height persist per
workspace via the default-layout extension.

Drag-resize of the dock height is deferred (DragResizeHandle needs a dock
sign case); height is the persisted default for now. Boot verified via
testmode; full suite green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/builtin/output/dock_status_item_test.dart

@@ -0,0 +1,52 @@
+/// T-54: the merged health + dock-toggle status-bar widget (D-87).
+library;
+
+import 'package:clide/builtin/default_layout/default_layout.dart';
+import 'package:clide/builtin/output/output.dart';
+import 'package:clide/kernel/kernel.dart';
+import 'package:clide/widgets/widgets.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import '../../helpers/kernel_fixture.dart';
+import '../../helpers/widget_harness.dart';
+
+bool _textIs(Object? w, String s) => w is ClideText && w.data == s;
+
+void main() {
+  late KernelFixture f;
+
+  setUp(() async {
+    f = await KernelFixture.create();
+    f.services.extensions.register(DefaultLayoutExtension());
+    await f.services.extensions.activate('builtin.default-layout');
+  });
+  tearDown(() => f.dispose());
+
+  testWidgets('reads clean (green ✓), then shows the error count', (tester) async {
+    await tester.pumpWidget(harness(f, const DockStatusItem()));
+    await tester.pumpAndSettle();
+    expect(find.byWidgetPredicate((w) => _textIs(w, '✓')), findsOneWidget);
+
+    f.services.logRing.add(LogRecord(level: LogLevel.error, source: 'x', message: 'boom', timestamp: DateTime.utc(2026)));
+    await tester.pumpAndSettle();
+    expect(find.byWidgetPredicate((w) => _textIs(w, '✕ 1')), findsOneWidget);
+  });
+
+  testWidgets('shows a warn count when there are warnings but no errors', (tester) async {
+    f.services.logRing.add(LogRecord(level: LogLevel.warn, source: 'x', message: 'w', timestamp: DateTime.utc(2026)));
+    await tester.pumpWidget(harness(f, const DockStatusItem()));
+    await tester.pumpAndSettle();
+    expect(find.byWidgetPredicate((w) => _textIs(w, '⚠ 1')), findsOneWidget);
+  });
+
+  testWidgets('tapping toggles the dock open', (tester) async {
+    await tester.pumpWidget(harness(f, const DockStatusItem()));
+    await tester.pumpAndSettle();
+    expect(f.services.arrangement.isVisible(Slots.dock), isFalse);
+    await tester.tap(find.byType(DockStatusItem));
+    await tester.pumpAndSettle();
+    expect(f.services.arrangement.isVisible(Slots.dock), isTrue);
+    expect(find.byWidgetPredicate((w) => _textIs(w, '▼ Output ')), findsOneWidget);
+  });
+}

test/builtin/output/output_extension_test.dart

@@ -0,0 +1,42 @@
+/// T-54: OutputExtension wires the dock tab, the status toggle, and the
+/// dock.toggle command (D-87).
+library;
+
+import 'package:clide/builtin/default_layout/default_layout.dart';
+import 'package:clide/builtin/output/output.dart';
+import 'package:clide/extension/extension.dart';
+import 'package:clide/kernel/kernel.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import '../../helpers/kernel_fixture.dart';
+
+void main() {
+  late KernelFixture f;
+
+  setUp(() async {
+    f = await KernelFixture.create();
+    f.services.extensions
+      ..register(DefaultLayoutExtension())
+      ..register(OutputExtension());
+    await f.services.extensions.activate('builtin.default-layout');
+    await f.services.extensions.activate('builtin.output');
+  });
+  tearDown(() => f.dispose());
+
+  test('contributes the Output dock tab, a status item, and dock.toggle', () {
+    final ext = OutputExtension();
+    final tabs = ext.contributions.whereType<TabContribution>();
+    expect(tabs.any((t) => t.id == 'output.panel' && t.slot == Slots.dock), isTrue);
+    expect(ext.contributions.whereType<StatusItemContribution>(), isNotEmpty);
+    expect(f.services.commands.get('dock.toggle'), isNotNull);
+  });
+
+  test('dock.toggle opens the dock + activates Output, then closes it', () async {
+    expect(f.services.arrangement.isVisible(Slots.dock), isFalse);
+    await f.services.commands.execute('dock.toggle');
+    expect(f.services.arrangement.isVisible(Slots.dock), isTrue);
+    expect(f.services.panels.activeTabIn(Slots.dock), 'output.panel');
+    await f.services.commands.execute('dock.toggle');
+    expect(f.services.arrangement.isVisible(Slots.dock), isFalse);
+  });
+}