docs: update CLAUDE.md and COMPONENT_GUIDE.md for composable Sidebar

- Add Sidebar, SidebarTree, useStarred to import paths
- Update navigation decision tree with compound component entries
- Replace old Sidebar props description with compound API
- Add standard page layout composition pattern for new Sidebar

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -40,6 +40,10 @@ import { Button, Input } from '../design-system/primitives'
 import { Modal, DataTable, KpiStrip, SplitPane, EntityList, LogViewer } from '../design-system/composites'
 import type { Column, KpiItem, LogEntry } from '../design-system/composites'
 import { AppShell } from '../design-system/layout/AppShell'
+import { Sidebar } from '../design-system/layout/Sidebar/Sidebar'
+import { SidebarTree } from '../design-system/layout/Sidebar/SidebarTree'
+import type { SidebarTreeNode } from '../design-system/layout/Sidebar/SidebarTree'
+import { useStarred } from '../design-system/layout/Sidebar/useStarred'
 import { ThemeProvider } from '../design-system/providers/ThemeProvider'
 ```
 
@@ -93,6 +97,10 @@ import { Button, AppShell, ThemeProvider } from '@cameleer/design-system'
 // All components from single entry
 import { Button, Input, Modal, DataTable, KpiStrip, SplitPane, EntityList, LogViewer, StatusText, AppShell } from '@cameleer/design-system'
 
+// Sidebar (compound component — compose your own navigation)
+import { Sidebar, SidebarTree, useStarred } from '@cameleer/design-system'
+import type { SidebarTreeNode } from '@cameleer/design-system'
+
 // Types
 import type { Column, DataTableProps, SearchResult, KpiItem, LogEntry } from '@cameleer/design-system'