feat(workspace): one global switcher anchor in the shell sidebar

The switcher used to be embedded per page (Flows/Runs/Audit/
Approvals) — invisible on the other five pages and sitting in a
different corner depending on the page (persona review 2026-08-27,
consensus finding). It now lives ONCE in the sidebar, above the
destinations: active project/area always visible, opens the same
menu everywhere, Cmd+P from anywhere. The shell listens to the
workspace, so the sidebar endpoint label can no longer lag a
sealed switch until the next health tick.

Also in this rebuild:

* Stopped sealed areas ask before starting ("Start area X?") —
  a context switch must never boot a hub daemon as a click
  side-effect; running areas keep switching with one click.
* The switcher tooltip told a wrong scope ("filters this view") —
  it now says the choice applies everywhere and stamps new runs.
* The aggregated sealed row explains itself in place (names can
  reveal client identities) and links to the Settings toggle
  (Settings dialog gained an initialCategory jump).
* The active entry carries a checkmark in the menu.
* The Cmd+K palette knows projects and areas, ranked by recent
  use; sealed names honour the privacy setting — while hidden,
  the palette offers the guarded picker instead of the names.
* The runs empty state names the active project filter as the
  cause ("No runs in project X" + show-all action) instead of
  claiming the feature is off.

Tests updated to the anchor and made hermetic (scriptable
projects on the fake hub, sealed-area fake); new coverage for the
checkmark, the why-line, and the start confirmation.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/pages/approvals.dart

@@ -376,8 +376,6 @@ class _ApprovalsPageState extends State<ApprovalsPage> {
           ),
         ),
         actions: [
-          const ChainWorkspaceSwitcher(),
-          const SizedBox(width: ChainSpace.md),
           IconButton(
             icon: const Icon(Icons.help_outline, size: 18),
             tooltip: AppLocalizations.of(context)!.helpTooltip,

lib/pages/audit.dart

@@ -306,11 +306,9 @@ class _AuditPageState extends State<AuditPage> {
       appBar: AppBar(
         title: Text(AppLocalizations.of(context)!.auditTitle),
         actions: [
-          const ChainWorkspaceSwitcher(),
-          const SizedBox(width: ChainSpace.md),
-          // Narrow windows can't fit the inline chip row next to the
-          // workspace switcher — collapse to a checkmark menu so the
-          // app bar never overflows (responsive_test.dart pins this).
+          // Narrow windows can't fit the inline chip row — collapse
+          // to a checkmark menu so the app bar never overflows
+          // (responsive_test.dart pins this).
           Padding(
             padding: const EdgeInsets.only(right: ChainSpace.lg),
             child: MediaQuery.sizeOf(context).width < 900

lib/pages/flows.dart

@@ -23,7 +23,6 @@ import '../data/store_caps.dart';
 import '../data/workspace.dart';
 import '../l10n/app_localizations.dart';
 import '../widgets/chain_install_confirm.dart';
-import '../widgets/chain_workspace_switcher.dart';
 
 class FlowsPage extends StatefulWidget {
   /// Pre-load this flow when the editor first builds. Studio
@@ -220,11 +219,9 @@ class _FlowsPageState extends State<FlowsPage> {
             onInstallCapability: _onInstallCapability,
             onAddModuleSource: _onAddModuleSource,
             activeProject: Workspace.instance.activeSlug,
-            // Same switcher as Audit/Approvals/Runs, hosted in the
-            // editor's toolbar (the page's single header): it
-            // filters the flow list and is the project a new flow
-            // gets stamped with.
-            toolbarTrailing: const ChainWorkspaceSwitcher(),
+            // The workspace switcher lives ONCE in the shell sidebar
+            // (global anchor) — the editor toolbar no longer hosts
+            // its own copy.
             // Native file dialog for the Run tab's file inputs —
             // nobody should have to type an absolute path by hand.
             onPickFile: _pickFlowInputFile,

lib/pages/runs.dart

@@ -254,6 +254,14 @@ class _RunsPageState extends State<RunsPage> {
     }
   }
 
+  /// Display name of the filtered project ("General" localized).
+  String _activeProjectLabel(AppLocalizations l) {
+    final ws = Workspace.instance;
+    final p = ws.active;
+    if (p == null) return ws.activeSlug;
+    return p.slug == 'general' ? l.workspaceDefaultProject : p.name;
+  }
+
   Future<void> _cancel(DetachedRun run) async {
     final l = AppLocalizations.of(context)!;
     setState(() => _cancelling.add(run.id));
@@ -333,8 +341,6 @@ class _RunsPageState extends State<RunsPage> {
       appBar: AppBar(
         title: Text(l.runsTitle),
         actions: [
-          const ChainWorkspaceSwitcher(),
-          const SizedBox(width: ChainSpace.md),
           IconButton(
             icon: const Icon(Icons.help_outline, size: 18),
             tooltip: l.helpTooltip,
@@ -361,22 +367,41 @@ class _RunsPageState extends State<RunsPage> {
               updating: _updatingHub,
             )
           : _runs.isEmpty
-          ? ChainEmptyState(
-              icon: Icons.rocket_launch_outlined,
-              title: l.runsEmptyTitle,
-              // The hub reports whether the operator enabled the
-              // feature — never claim "switched off" while it is on
-              // and there simply are no runs yet (usertest finding).
-              hint: _detachedEnabled ? l.runsEmptyEnabledHint : l.runsEmptyHint,
-              // The guide carries the plain-language explanation plus
-              // the exact operator steps (config snippet) — a click
-              // target instead of a raw config key in the hint.
-              action: OutlinedButton.icon(
-                icon: const Icon(Icons.menu_book_outlined, size: 16),
-                label: Text(l.runsEmptyGuideButton),
-                onPressed: () => showFaiDoc(context, 'runs'),
-              ),
-            )
+          // With an active project filter the honest cause is the
+          // filter, not the feature — name the project and offer the
+          // way out instead of the enable-the-feature guide
+          // (persona finding: the old hint claimed a wrong cause).
+          ? (_detachedEnabled && !Workspace.instance.isAll
+                ? ChainEmptyState(
+                    icon: Icons.rocket_launch_outlined,
+                    title: l.runsEmptyFilteredTitle(_activeProjectLabel(l)),
+                    hint: l.runsEmptyFilteredHint,
+                    action: OutlinedButton.icon(
+                      icon: const Icon(Icons.grid_view_outlined, size: 16),
+                      label: Text(l.runsEmptyShowAll),
+                      onPressed: () => Workspace.instance.setActive(''),
+                    ),
+                  )
+                : ChainEmptyState(
+                    icon: Icons.rocket_launch_outlined,
+                    title: l.runsEmptyTitle,
+                    // The hub reports whether the operator enabled the
+                    // feature — never claim "switched off" while it is
+                    // on and there simply are no runs yet (usertest
+                    // finding).
+                    hint: _detachedEnabled
+                        ? l.runsEmptyEnabledHint
+                        : l.runsEmptyHint,
+                    // The guide carries the plain-language explanation
+                    // plus the exact operator steps (config snippet) —
+                    // a click target instead of a raw config key in
+                    // the hint.
+                    action: OutlinedButton.icon(
+                      icon: const Icon(Icons.menu_book_outlined, size: 16),
+                      label: Text(l.runsEmptyGuideButton),
+                      onPressed: () => showFaiDoc(context, 'runs'),
+                    ),
+                  ))
           : ListView.separated(
               padding: const EdgeInsets.all(ChainSpace.lg),
               itemCount: _runs.length,