Sprint: debug, zichtbaarheid componenten (#165)

* feat(debug-store): Zustand store met hydration-flag voor debug-modus

* feat(status-bar): dev-only debug-toggle via geïsoleerde sub-component

* feat(globals.css): debug-mode overlay CSS voor data-debug-id elementen

* feat(shared): data-debug-id+label op navigatie-componenten

* feat(shared): data-debug-id+label op form/select-componenten

* feat(shared): data-debug-id+label op display-componenten

stores/debug-store.ts

@@ -0,0 +1,15 @@
+import { create } from 'zustand'
+
+type DebugStore = {
+  debugMode: boolean
+  _hydrated: boolean
+  hydrate: (value: boolean) => void
+  toggleDebugMode: () => void
+}
+
+export const useDebugStore = create<DebugStore>((set, get) => ({
+  debugMode: false,
+  _hydrated: false,
+  hydrate: (v) => set({ debugMode: v, _hydrated: true }),
+  toggleDebugMode: () => set({ debugMode: !get().debugMode }),
+}))