fase(10): frontend shadcn-ui shell with auth

frontend/src/stores/uiStore.ts

@@ -0,0 +1,17 @@
+import { create } from 'zustand'
+
+interface UIState {
+  sidebarCollapsed: boolean
+  commandPaletteOpen: boolean
+  toggleSidebar: () => void
+  setSidebarCollapsed: (v: boolean) => void
+  setCommandPaletteOpen: (v: boolean) => void
+}
+
+export const useUIStore = create<UIState>((set) => ({
+  sidebarCollapsed: false,
+  commandPaletteOpen: false,
+  toggleSidebar: () => set(s => ({ sidebarCollapsed: !s.sidebarCollapsed })),
+  setSidebarCollapsed: (v) => set({ sidebarCollapsed: v }),
+  setCommandPaletteOpen: (v) => set({ commandPaletteOpen: v }),
+}))