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>

lib/builtin/default_layout/src/extension.dart

@@ -144,6 +144,10 @@ class DefaultLayoutExtension extends ClideExtension {
     if (sidebarSize != null) ctx.arrangement.setSize(Slots.sidebar, sidebarSize);
     final contextSize = s.get<double>(_kContextSize);
     if (contextSize != null) ctx.arrangement.setSize(Slots.contextPanel, contextSize);
+    final dockVisible = s.get<bool>(_kDockVisible);
+    if (dockVisible != null) ctx.arrangement.setVisible(Slots.dock, dockVisible);
+    final dockSize = s.get<double>(_kDockSize);
+    if (dockSize != null) ctx.arrangement.setSize(Slots.dock, dockSize);
     final editorRatio = s.get<double>(_kEditorRatio);
     if (editorRatio != null) ctx.arrangement.setEditorRatio(editorRatio);
     final activeLeft = s.get<String>(_kActiveLeft);
@@ -161,6 +165,8 @@ class DefaultLayoutExtension extends ClideExtension {
     s.set(_kSidebarSize, a.sizeOf(Slots.sidebar));
     s.set(_kContextSize, a.sizeOf(Slots.contextPanel));
     s.set(_kEditorRatio, a.editorRatio);
+    s.set(_kDockVisible, a.isVisible(Slots.dock));
+    s.set(_kDockSize, a.sizeOf(Slots.dock));
   }
 
   void _persistActiveTabs(ClideExtensionContext ctx) {
@@ -179,6 +185,8 @@ class DefaultLayoutExtension extends ClideExtension {
   static const _kEditorRatio = 'project.layout.editor.ratio';
   static const _kActiveLeft = 'project.layout.sidebar.activeTab';
   static const _kActiveRight = 'project.layout.context.activeTab';
+  static const _kDockVisible = 'project.layout.dock.visible';
+  static const _kDockSize = 'project.layout.dock.size';
 
   Future<IpcResponse> _reset(List<String> args) async {
     final preset = _preset;

lib/builtin/output/output.dart

@@ -1,2 +1,4 @@
+export 'src/dock_status_item.dart';
+export 'src/extension.dart';
 export 'src/output_controller.dart';
 export 'src/output_view.dart';

lib/builtin/output/src/dock_status_item.dart

@@ -0,0 +1,88 @@
+/// Status-bar widget for the output dock (T-54 / D-87): merged health +
+/// toggle. Replaces the old app-status item — green ✓ when the log is clean,
+/// ⚠/✕ counts when not; click (or ⌘J) toggles the dock; chevron shows state.
+library;
+
+import 'dart:async';
+
+import 'package:clide/kernel/kernel.dart';
+import 'package:clide/widgets/widgets.dart';
+import 'package:flutter/widgets.dart';
+
+class DockStatusItem extends StatefulWidget {
+  const DockStatusItem({super.key});
+
+  @override
+  State<DockStatusItem> createState() => _DockStatusItemState();
+}
+
+class _DockStatusItemState extends State<DockStatusItem> {
+  KernelServices? _kernel;
+  StreamSubscription<void>? _ringSub;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final k = ClideKernel.of(context);
+    if (identical(k, _kernel)) return;
+    _kernel = k;
+    _ringSub?.cancel();
+    _ringSub = k.logRing.changes.listen((_) {
+      if (mounted) setState(() {});
+    });
+  }
+
+  void _toggle(KernelServices kernel) {
+    final a = kernel.arrangement;
+    final opening = !a.isVisible(Slots.dock);
+    a.setVisible(Slots.dock, opening);
+    if (opening && kernel.panels.activeTabIn(Slots.dock) == null) {
+      kernel.panels.activateTab(Slots.dock, 'output.panel');
+    }
+  }
+
+  @override
+  void dispose() {
+    _ringSub?.cancel();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final kernel = ClideKernel.of(context);
+    return ListenableBuilder(
+      listenable: kernel.arrangement,
+      builder: (ctx, _) {
+        final tokens = ClideTheme.of(ctx).surface;
+        final open = kernel.arrangement.isVisible(Slots.dock);
+        final errors = kernel.logRing.countAtLeast(LogLevel.error);
+        final warns = kernel.logRing.countAtLeast(LogLevel.warn) - errors;
+        final (String badge, Color color) = errors > 0
+            ? ('✕ $errors', tokens.statusError)
+            : warns > 0
+                ? ('⚠ $warns', tokens.statusWarning)
+                : ('✓', tokens.statusSuccess);
+        return Semantics(
+          button: true,
+          label: 'toggle output dock',
+          child: GestureDetector(
+            onTap: () => _toggle(kernel),
+            child: MouseRegion(
+              cursor: SystemMouseCursors.click,
+              child: Padding(
+                padding: const EdgeInsets.symmetric(horizontal: 8),
+                child: Row(
+                  mainAxisSize: MainAxisSize.min,
+                  children: [
+                    ClideText('${open ? '▼' : '▲'} Output ', fontSize: clideFontCaption, color: tokens.globalForeground),
+                    ClideText(badge, fontSize: clideFontCaption, color: color),
+                  ],
+                ),
+              ),
+            ),
+          ),
+        );
+      },
+    );
+  }
+}

lib/builtin/output/src/extension.dart

@@ -0,0 +1,63 @@
+/// The output-dock builtin (T-54 / D-87): contributes the Output tab + the
+/// merged health/toggle status-bar widget, and the `dock.toggle` command.
+library;
+
+import 'package:clide/builtin/output/src/dock_status_item.dart';
+import 'package:clide/builtin/output/src/output_view.dart';
+import 'package:clide/clide.dart';
+import 'package:clide/extension/extension.dart';
+import 'package:clide/kernel/kernel.dart';
+
+class OutputExtension extends ClideExtension {
+  ClideExtensionContext? _ctx;
+
+  @override
+  String get id => 'builtin.output';
+  @override
+  String get title => 'Output';
+  @override
+  String get version => '0.1.0';
+
+  /// The dock slot is registered by the default-layout preset; depend on it so
+  /// the slot exists before this tab contributes.
+  @override
+  List<String> get dependsOn => const ['builtin.default-layout'];
+
+  @override
+  Future<void> activate(ClideExtensionContext ctx) async {
+    _ctx = ctx;
+  }
+
+  @override
+  List<ContributionPoint> get contributions => [
+        TabContribution(
+          id: 'output.panel',
+          slot: Slots.dock,
+          title: 'Output',
+          priority: -100, // sort before Problems in the dock tab bar
+          build: (ctx) => OutputView(ring: ClideKernel.of(ctx).logRing),
+        ),
+        StatusItemContribution(
+          id: 'output.dock-toggle',
+          priority: 100, // right group, replacing the old app-status item
+          build: (_) => const DockStatusItem(),
+        ),
+        CommandContribution(
+          id: 'dock.toggle',
+          command: 'dock.toggle',
+          title: 'Toggle output dock',
+          defaultBinding: 'ctrl+j',
+          run: (_) async {
+            final ctx = _ctx;
+            if (ctx == null) return IpcResponse.ok(id: '', data: const {});
+            final a = ctx.arrangement;
+            final opening = !a.isVisible(Slots.dock);
+            a.setVisible(Slots.dock, opening);
+            if (opening && ctx.panels.activeTabIn(Slots.dock) == null) {
+              ctx.panels.activateTab(Slots.dock, 'output.panel');
+            }
+            return IpcResponse.ok(id: '', data: {'dock': opening});
+          },
+        ),
+      ];
+}

lib/builtin/problems/src/extension.dart

@@ -1,7 +1,6 @@
 import 'package:clide/builtin/problems/src/problems_view.dart';
 import 'package:clide/extension/extension.dart';
 import 'package:clide/kernel/kernel.dart';
-import 'package:clide/widgets/widgets.dart';
 
 class ProblemsExtension extends ClideExtension {
   @override
@@ -15,11 +14,12 @@ class ProblemsExtension extends ClideExtension {
 
   @override
   List<ContributionPoint> get contributions => [
+        // Moved out of the sidebar into the bottom dock (D-87): no duplication,
+        // and the dock's width fits `severity · file:line · message` rows.
         TabContribution(
           id: 'problems.panel',
-          slot: Slots.sidebar,
+          slot: Slots.dock,
           title: 'Problems',
-          icon: PhosphorIcons.warningCircle,
           titleKey: 'tab.title',
           i18nNamespace: id,
           priority: -50,