feat: Add directory tree tab to session files

web/src/hooks/queries/useSessionDirectory.ts

@@ -0,0 +1,49 @@
+import { useQuery } from '@tanstack/react-query'
+import type { ApiClient } from '@/api/client'
+import type { DirectoryEntry } from '@/types/api'
+import { queryKeys } from '@/lib/query-keys'
+
+export function useSessionDirectory(
+    api: ApiClient | null,
+    sessionId: string | null,
+    path: string,
+    options?: { enabled?: boolean }
+): {
+    entries: DirectoryEntry[]
+    error: string | null
+    isLoading: boolean
+    refetch: () => Promise<unknown>
+} {
+    const resolvedSessionId = sessionId ?? 'unknown'
+    const enabled = Boolean(api && sessionId) && (options?.enabled ?? true)
+
+    const query = useQuery({
+        queryKey: queryKeys.sessionDirectory(resolvedSessionId, path),
+        queryFn: async () => {
+            if (!api || !sessionId) {
+                throw new Error('Session unavailable')
+            }
+
+            const response = await api.listSessionDirectory(sessionId, path)
+            if (!response.success) {
+                return { entries: [], error: response.error ?? 'Failed to list directory' }
+            }
+
+            return { entries: response.entries ?? [], error: null }
+        },
+        enabled,
+    })
+
+    const queryError = query.error instanceof Error
+        ? query.error.message
+        : query.error
+            ? 'Failed to list directory'
+            : null
+
+    return {
+        entries: query.data?.entries ?? [],
+        error: queryError ?? query.data?.error ?? null,
+        isLoading: query.isLoading,
+        refetch: query.refetch
+    }
+}

web/src/hooks/useAppGoBack.ts

@@ -5,6 +5,7 @@ export function useAppGoBack(): () => void {
     const navigate = useNavigate()
     const router = useRouter()
     const pathname = useLocation({ select: (location) => location.pathname })
+    const search = useLocation({ select: (location) => location.search })
 
     return useCallback(() => {
         // Use explicit path navigation for consistent behavior across all environments
@@ -22,7 +23,13 @@ export function useAppGoBack(): () => void {
         // For single file view, go back to files list
         if (pathname.match(/^\/sessions\/[^/]+\/file$/)) {
             const filesPath = pathname.replace(/\/file$/, '/files')
-            navigate({ to: filesPath })
+
+            const tab = (search && typeof search === 'object' && 'tab' in search)
+                ? (search as { tab?: unknown }).tab
+                : undefined
+            const nextSearch = tab === 'directories' ? { tab: 'directories' as const } : {}
+
+            navigate({ to: filesPath, search: nextSearch })
             return
         }
 
@@ -35,5 +42,5 @@ export function useAppGoBack(): () => void {
 
         // Fallback to history.back() for other cases
         router.history.back()
-    }, [navigate, pathname, router])
+    }, [navigate, pathname, router, search])
 }