feat(sidebar): cockpit redesign with grouped stacks and activity footer (#702)

* chore: ignore .superpowers/ brainstorm scratch dir

* feat(sidebar): add useStackMenuItems hook with grouped menu model

Pure transform hook that converts StackMenuCtx into four ordered MenuGroup
arrays (inspect, organize, lifecycle, destructive). Shared type contract in
sidebar-types.ts gives both the ContextMenu and DropdownMenu a single source
of truth so they cannot drift. Covered by 8 unit tests.

* refactor(sidebar): stabilize useStackMenuItems memoization deps

Destructure menuVisibility flags into primitive deps so inline object
literals from callers do not defeat memoization. Add a test confirming
isBusy disables all lifecycle items.

* feat(sidebar): add usePinnedStacks hook with per-node localStorage

* refactor(sidebar): stabilize usePinnedStacks eviction signal and isPinned dep

Change evictedOldest shape to { file, seq } so consumer effects re-fire on
repeated evictions. Narrow isPinned's useCallback dep to the current node's
pinned list so it only rebinds on local changes. Add test for eviction
side-effect and a second test for the seq counter.

* feat(sidebar): add useSidebarGroupCollapse hook with per-node keys

* refactor(sidebar): tighten useSidebarGroupCollapse effect ordering

Collapse the two write/read effects into a single skip-next-write ref
pattern so switching nodes no longer writes the previous node's map under
the new key before hydration. Also skip the no-op mount write. Add test
for setCollapsed.

* feat(sidebar): add row + group-header style helpers

* feat(sidebar): add SidebarBrand with mono kicker + serif hero

* feat(sidebar): add SidebarActions wrapper for create + scan

* feat(sidebar): extract SidebarSearch with kbd pill

* feat(sidebar): add StackRow with cyan-rail active state

* refactor(sidebar): dedupe tooltip markup in StackRow, widen test coverage

Extract a local RowTooltip helper so the update and git-pending branches
share the CursorProvider scaffolding. Add four behavioral tests covering
click, keyboard activation, kebab stop-propagation, and the busy loader
branch.

* feat(sidebar): unify context + kebab menus via useStackMenuItems

* feat(sidebar): add StackGroup with collapse and pinned variant

* feat(sidebar): add StackList with pinned + label groups

* feat(sidebar): add SidebarActivityTicker with idle fallback

* feat(sidebar): add StackSidebar container composing the regions

* feat(sidebar): replace sidebar block with StackSidebar composition

* docs(sidebar): add stack sidebar feature page with screenshots

* fix(sidebar): satisfy react-hooks purity and memoization rules

* fix(sidebar): restore "Sencho Logo" alt text for E2E selector

frontend/src/hooks/useStackMenuItems.tsx

@@ -0,0 +1,86 @@
+import { useMemo } from 'react';
+import {
+  Activity,
+  ArrowUpRight,
+  BellRing,
+  Download,
+  Pin,
+  PinOff,
+  Play,
+  RefreshCw,
+  RotateCw,
+  Square,
+  Tag,
+  Trash2,
+} from 'lucide-react';
+import type { MenuGroup, MenuItem, StackMenuCtx } from '@/components/sidebar/sidebar-types';
+
+export function useStackMenuItems(_file: string, ctx: StackMenuCtx): MenuGroup[] {
+  const {
+    stackStatus, hasPort, isBusy, isPaid, canDelete, isPinned, labels,
+    openAlertSheet, openAutoHeal, checkUpdates, openStackApp,
+    deploy, stop, restart, update, remove, pin, unpin, toggleLabel,
+    menuVisibility,
+  } = ctx;
+  const { showDeploy, showStop, showRestart, showUpdate } = menuVisibility;
+
+  return useMemo(() => {
+    const groups: MenuGroup[] = [];
+
+    const inspect: MenuItem[] = [
+      { id: 'alerts', label: 'Alerts', icon: BellRing, shortcut: 'A', onSelect: openAlertSheet },
+    ];
+    if (isPaid) {
+      inspect.push({ id: 'auto-heal', label: 'Auto-Heal', icon: Activity, shortcut: 'H', onSelect: openAutoHeal });
+    }
+    inspect.push({ id: 'check-updates', label: 'Check updates', icon: RefreshCw, shortcut: 'U', onSelect: checkUpdates });
+    if (stackStatus === 'running' && hasPort) {
+      inspect.push({ id: 'open-app', label: 'Open App', icon: ArrowUpRight, shortcut: '↗', onSelect: openStackApp });
+    }
+    groups.push({ id: 'inspect', items: inspect });
+
+    const organize: MenuItem[] = [];
+    if (isPaid) {
+      organize.push({
+        id: 'labels',
+        label: 'Labels',
+        icon: Tag,
+        shortcut: 'L ›',
+        onSelect: () => {},
+        subItems: labels.map(l => ({
+          id: `label:${l.id}`,
+          label: l.name,
+          icon: Tag,
+          onSelect: () => toggleLabel(l.id),
+        })),
+      });
+    }
+    organize.push(
+      isPinned
+        ? { id: 'pin', label: 'Unpin', icon: PinOff, shortcut: 'P', onSelect: unpin }
+        : { id: 'pin', label: 'Pin to top', icon: Pin, shortcut: 'P', onSelect: pin }
+    );
+    groups.push({ id: 'organize', items: organize });
+
+    const lifecycle: MenuItem[] = [];
+    if (showDeploy) lifecycle.push({ id: 'deploy', label: 'Deploy', icon: Play, shortcut: '⌘↵', onSelect: deploy, disabled: isBusy });
+    if (showStop) lifecycle.push({ id: 'stop', label: 'Stop', icon: Square, shortcut: '⌘.', onSelect: stop, disabled: isBusy });
+    if (showRestart) lifecycle.push({ id: 'restart', label: 'Restart', icon: RotateCw, shortcut: '⌘R', onSelect: restart, disabled: isBusy });
+    if (showUpdate) lifecycle.push({ id: 'update', label: 'Update', icon: Download, shortcut: '⌘↑', onSelect: update, disabled: isBusy });
+    if (lifecycle.length > 0) groups.push({ id: 'lifecycle', items: lifecycle });
+
+    if (canDelete) {
+      groups.push({
+        id: 'destructive',
+        items: [{ id: 'delete', label: 'Delete', icon: Trash2, shortcut: '⌘⌫', destructive: true, onSelect: remove }],
+      });
+    }
+
+    return groups;
+  }, [
+    stackStatus, hasPort, isBusy, isPaid, canDelete, isPinned, labels,
+    showDeploy, showStop, showRestart, showUpdate,
+    openAlertSheet, openAutoHeal, checkUpdates, openStackApp,
+    deploy, stop, restart, update, remove, pin, unpin, toggleLabel,
+  ]);
+}