migrate the menu bar onto ClideAnchoredOverlay + ClideMenu (T-286)

Replace the per-button hand-rolled LayerLink/OverlayEntry/barrier and the
bespoke MenuDropdown + MenuItemRow with the shared popover primitive (D-88).
A small _MenuOverlayAdapter bridges the single-open MenuBarController to each
button's ClideOverlayController, so one source of truth drives open/close,
hover-switch, Alt mnemonics, and Left/Right menu switching (onArrowLeft/Right).
menu_dropdown.dart and menu_item_row.dart are deleted (absorbed by ClideMenu).

Behaviour and a11y are unchanged; menu_bar_test + app_test stay green.

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

lib/builtin/menubar/src/menu_bar.dart

@@ -5,7 +5,6 @@ import 'package:clide/widgets/widgets.dart';
 import 'package:flutter/widgets.dart';
 
 import 'extension.dart' show buildClideMenuTree;
-import 'menu_dropdown.dart';
 import 'menu_model.dart';
 
 /// Open/close state for the application menu bar (T-48). Owned by the root
@@ -102,87 +101,83 @@ class _TopMenuButton extends StatefulWidget {
   State<_TopMenuButton> createState() => _TopMenuButtonState();
 }
 
-class _TopMenuButtonState extends State<_TopMenuButton> {
-  final LayerLink _link = LayerLink();
-  OverlayEntry? _entry;
-
-  @override
-  void initState() {
-    super.initState();
-    widget.controller.addListener(_sync);
+/// Adapts the shared [MenuBarController] (single-open across buttons) to the
+/// per-button [ClideOverlayController] the primitive drives. Reads/writes go
+/// straight through to the bar so there's one source of truth; it notifies when
+/// this button's open state flips so the anchored overlay opens/closes in step.
+class _MenuOverlayAdapter extends ClideOverlayController {
+  _MenuOverlayAdapter(this._bar, this._index) : _last = _bar.openIndex == _index {
+    _bar.addListener(_onBar);
   }
 
-  @override
-  void didUpdateWidget(_TopMenuButton old) {
-    super.didUpdateWidget(old);
-    if (!identical(old.controller, widget.controller)) {
-      old.controller.removeListener(_sync);
-      widget.controller.addListener(_sync);
+  final MenuBarController _bar;
+  final int _index;
+  bool _last;
+
+  void _onBar() {
+    final now = _bar.openIndex == _index;
+    if (now != _last) {
+      _last = now;
+      notifyListeners();
     }
-    // NB: do NOT markNeedsBuild the open entry here — didUpdateWidget runs
-    // during the parent's build, and marking an overlay entry mid-build is
-    // illegal. The menu set doesn't change while a menu is open in practice;
-    // the panel is rebuilt fresh on the next open.
   }
 
+  @override
+  bool get isOpen => _bar.openIndex == _index;
+  @override
+  void open() => _bar.open(_index);
+  @override
+  void close() => _bar.close();
+  @override
+  void toggle() => _bar.toggle(_index);
+
   @override
   void dispose() {
-    widget.controller.removeListener(_sync);
-    _entry?.remove();
-    _entry = null;
+    _bar.removeListener(_onBar);
     super.dispose();
   }
+}
 
-  void _sync() {
-    final shouldOpen = widget.controller.openIndex == widget.index;
-    if (shouldOpen && _entry == null) {
-      _entry = OverlayEntry(builder: _buildOverlay);
-      Overlay.of(context, rootOverlay: true).insert(_entry!);
-    } else if (!shouldOpen && _entry != null) {
-      _entry!.remove();
-      _entry = null;
-    }
-  }
+class _TopMenuButtonState extends State<_TopMenuButton> {
+  late final _MenuOverlayAdapter _overlay = _MenuOverlayAdapter(widget.controller, widget.index);
 
-  void _activate(String commandId) {
-    widget.controller.close();
-    unawaited(widget.kernel.commands.execute(commandId));
-  }
-
-  Widget _buildOverlay(BuildContext context) {
-    return Stack(
-      children: [
-        Positioned.fill(
-          child: GestureDetector(behavior: HitTestBehavior.opaque, onTap: widget.controller.close),
-        ),
-        CompositedTransformFollower(
-          link: _link,
-          showWhenUnlinked: false,
-          targetAnchor: Alignment.bottomLeft,
-          followerAnchor: Alignment.topLeft,
-          offset: const Offset(0, 2),
-          child: Align(
-            alignment: Alignment.topLeft,
-            child: MenuDropdown(
-              menu: widget.menu,
-              onActivate: _activate,
-              onClose: widget.controller.close,
-              onPrevMenu: widget.controller.openPrev,
-              onNextMenu: widget.controller.openNext,
-            ),
-          ),
-        ),
-      ],
-    );
+  @override
+  void dispose() {
+    _overlay.dispose();
+    super.dispose();
   }
 
   @override
   Widget build(BuildContext context) {
     final tokens = ClideTheme.of(context).surface;
     final open = widget.controller.openIndex == widget.index;
-    return CompositedTransformTarget(
-      link: _link,
-      child: MouseRegion(
+    return ClideAnchoredOverlay(
+      controller: _overlay,
+      side: ClideAnchorSide.below,
+      align: ClideAnchorAlign.start,
+      offset: const Offset(0, 2),
+      autoFlip: false, // the bar sits at the top; menus always open downward
+      rootOverlay: true,
+      overlayBuilder: (ctx, ctrl) => ClideMenu(
+        onClose: ctrl.close,
+        onArrowLeft: widget.controller.openPrev,
+        onArrowRight: widget.controller.openNext,
+        entries: [
+          for (final node in widget.menu.items)
+            if (node is ResolvedItem)
+              ClideMenuItem(
+                label: node.title,
+                enabled: node.enabled,
+                trailing: node.keybinding != null
+                    ? ClideText(node.keybinding!, fontSize: clideFontSmall, fontFamily: clideMonoFamily, color: ClideTheme.of(ctx).surface.globalTextMuted)
+                    : null,
+                onSelect: () => unawaited(widget.kernel.commands.execute(node.commandId)),
+              )
+            else
+              const ClideMenuSeparator(),
+        ],
+      ),
+      anchor: MouseRegion(
         // Once a menu is open, hovering a sibling switches to it (Zed behavior).
         onEnter: (_) {
           if (widget.controller.isOpen) widget.controller.open(widget.index);

lib/builtin/menubar/src/menu_dropdown.dart

@@ -1,141 +0,0 @@
-import 'package:clide/kernel/kernel.dart';
-import 'package:flutter/services.dart';
-import 'package:flutter/widgets.dart';
-
-import 'menu_item_row.dart';
-import 'menu_model.dart';
-
-/// The open-menu panel (T-48): a `dropdown`-token surface listing the resolved
-/// items, with full keyboard navigation (Up/Down skip disabled rows +
-/// separators, Enter activates, Esc closes, Left/Right switch top menus).
-class MenuDropdown extends StatefulWidget {
-  const MenuDropdown({
-    super.key,
-    required this.menu,
-    required this.onActivate,
-    required this.onClose,
-    required this.onPrevMenu,
-    required this.onNextMenu,
-  });
-
-  final ResolvedMenu menu;
-  final void Function(String commandId) onActivate;
-  final VoidCallback onClose;
-  final VoidCallback onPrevMenu;
-  final VoidCallback onNextMenu;
-
-  @override
-  State<MenuDropdown> createState() => _MenuDropdownState();
-}
-
-class _MenuDropdownState extends State<MenuDropdown> {
-  final FocusNode _focus = FocusNode(debugLabel: 'menu-dropdown');
-  int _highlight = -1;
-
-  @override
-  void initState() {
-    super.initState();
-    WidgetsBinding.instance.addPostFrameCallback((_) {
-      if (mounted) _focus.requestFocus();
-    });
-  }
-
-  @override
-  void dispose() {
-    _focus.dispose();
-    super.dispose();
-  }
-
-  /// Indices into `menu.items` that are enabled command rows (navigable).
-  List<int> get _navigable {
-    final out = <int>[];
-    for (var i = 0; i < widget.menu.items.length; i++) {
-      final it = widget.menu.items[i];
-      if (it is ResolvedItem && it.enabled) out.add(i);
-    }
-    return out;
-  }
-
-  void _move(int dir) {
-    final nav = _navigable;
-    if (nav.isEmpty) return;
-    final pos = nav.indexOf(_highlight);
-    final next = pos < 0 ? (dir > 0 ? 0 : nav.length - 1) : (pos + dir) % nav.length;
-    setState(() => _highlight = nav[(next + nav.length) % nav.length]);
-  }
-
-  void _activateHighlighted() {
-    if (_highlight < 0) return;
-    final it = widget.menu.items[_highlight];
-    if (it is ResolvedItem && it.enabled) widget.onActivate(it.commandId);
-  }
-
-  KeyEventResult _onKey(FocusNode node, KeyEvent event) {
-    if (event is! KeyDownEvent && event is! KeyRepeatEvent) return KeyEventResult.ignored;
-    switch (event.logicalKey) {
-      case LogicalKeyboardKey.arrowDown:
-        _move(1);
-        return KeyEventResult.handled;
-      case LogicalKeyboardKey.arrowUp:
-        _move(-1);
-        return KeyEventResult.handled;
-      case LogicalKeyboardKey.enter:
-      case LogicalKeyboardKey.numpadEnter:
-      case LogicalKeyboardKey.space:
-        _activateHighlighted();
-        return KeyEventResult.handled;
-      case LogicalKeyboardKey.escape:
-        widget.onClose();
-        return KeyEventResult.handled;
-      case LogicalKeyboardKey.arrowLeft:
-        widget.onPrevMenu();
-        return KeyEventResult.handled;
-      case LogicalKeyboardKey.arrowRight:
-        widget.onNextMenu();
-        return KeyEventResult.handled;
-    }
-    return KeyEventResult.ignored;
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    final tokens = ClideTheme.of(context).surface;
-    return Focus(
-      focusNode: _focus,
-      onKeyEvent: _onKey,
-      child: IntrinsicWidth(
-        child: Container(
-          constraints: const BoxConstraints(minWidth: 220, maxWidth: 420),
-          decoration: BoxDecoration(
-            color: tokens.dropdownBackground,
-            border: Border.all(color: tokens.dropdownBorder),
-            borderRadius: BorderRadius.circular(6),
-            boxShadow: [BoxShadow(color: tokens.shadowAmbient, blurRadius: 12, offset: const Offset(0, 4))],
-          ),
-          padding: const EdgeInsets.symmetric(vertical: 4),
-          child: Column(
-            mainAxisSize: MainAxisSize.min,
-            crossAxisAlignment: CrossAxisAlignment.stretch,
-            children: [
-              for (var i = 0; i < widget.menu.items.length; i++) _row(i, widget.menu.items[i], tokens),
-            ],
-          ),
-        ),
-      ),
-    );
-  }
-
-  Widget _row(int index, ResolvedNode node, SurfaceTokens tokens) {
-    return switch (node) {
-      ResolvedSeparator() => Padding(
-          padding: const EdgeInsets.symmetric(vertical: 4),
-          child: Container(height: 1, color: tokens.dividerColor),
-        ),
-      ResolvedItem() => MenuItemRow(
-          item: node,
-          highlighted: index == _highlight,
-          onActivate: () => widget.onActivate(node.commandId),
-        ),
-    };
-  }
-}

lib/builtin/menubar/src/menu_item_row.dart

@@ -1,51 +0,0 @@
-import 'package:clide/kernel/kernel.dart';
-import 'package:clide/widgets/widgets.dart';
-import 'package:flutter/widgets.dart';
-
-import 'menu_model.dart';
-
-/// One command row in an open menu (T-48): label on the left, inline keybinding
-/// on the right (two-column control pattern). Disabled items render greyed and
-/// inert; the keyboard-highlighted row uses the hover background.
-class MenuItemRow extends StatelessWidget {
-  const MenuItemRow({super.key, required this.item, required this.highlighted, required this.onActivate});
-
-  final ResolvedItem item;
-  final bool highlighted;
-  final VoidCallback onActivate;
-
-  @override
-  Widget build(BuildContext context) {
-    final tokens = ClideTheme.of(context).surface;
-    final enabled = item.enabled;
-    return Semantics(
-      button: true,
-      enabled: enabled,
-      label: item.title,
-      child: ClideTappable(
-        onTap: enabled ? onActivate : null,
-        builder: (context, hovered, _) => Container(
-          color: enabled && (highlighted || hovered) ? tokens.listItemHoverBackground : null,
-          padding: const EdgeInsets.symmetric(horizontal: clideInsetText, vertical: 6),
-          child: Row(
-            children: [
-              Expanded(
-                child: ClideText(
-                  item.title,
-                  fontSize: clideFontCaption,
-                  color: enabled ? tokens.dropdownForeground : tokens.globalTextMuted,
-                  maxLines: 1,
-                  overflow: TextOverflow.ellipsis,
-                ),
-              ),
-              if (item.keybinding != null) ...[
-                const SizedBox(width: clideGapSection),
-                ClideText(item.keybinding!, fontSize: clideFontSmall, fontFamily: clideMonoFamily, color: tokens.globalTextMuted),
-              ],
-            ],
-          ),
-        ),
-      ),
-    );
-  }
-}