admin-panel: render sidebar icons, fix openKeys, persist collapse state

- VerticalNavMenu.vue now renders the icon: values that navMenuItems.ts
  already carried on 33 nodes but were never displayed, via the shared
  resolveIcon() map. Sub-menus and leaf items get a #icon slot each; ADV4's
  Menu shows icons only (labels hidden) once :inline-collapsed is true, which
  is now wired to the collapsed prop.
- Fixed openKeys: it previously started at [] and was only ever updated by
  user clicks, so a direct link or page refresh landed with the active
  item's parent submenu collapsed. It's now derived from the current route
  on load and on every navigation.
- Sidebar collapse state moves from a local ref in Main.vue to
  stores/layout.ts's existing (previously unused) sidebarCollapsed, persisted
  to localStorage so it survives a reload.

Verified: pnpm build passes.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/admin-panel/src/stores/layout.ts

@@ -5,6 +5,20 @@
 import { defineStore } from 'pinia';
 import themeConfig, { type ThemeMode } from '../themeConfig';
 
+const SIDEBAR_COLLAPSED_KEY = 'admin-panel:sidebarCollapsed';
+
+/** Reads the persisted collapse state, falling back to themeConfig's default
+ *  when localStorage is unavailable or has never been set. */
+function readPersistedCollapsed(): boolean {
+  if (typeof window === 'undefined') return themeConfig.sidebarCollapsed;
+  try {
+    const raw = window.localStorage.getItem(SIDEBAR_COLLAPSED_KEY);
+    return raw === null ? themeConfig.sidebarCollapsed : raw === '1';
+  } catch {
+    return themeConfig.sidebarCollapsed;
+  }
+}
+
 export const useLayoutStore = defineStore('layout', {
   state: () => ({
     windowWidth: typeof window !== 'undefined' ? window.innerWidth : 0,
@@ -12,7 +26,7 @@ export const useLayoutStore = defineStore('layout', {
     theme: themeConfig.theme as ThemeMode,
     // legacy state.js: sidebar visibility for the vertical nav menu
     isSidebarActive: true,
-    sidebarCollapsed: themeConfig.sidebarCollapsed,
+    sidebarCollapsed: readPersistedCollapsed(),
   }),
   getters: {
     // legacy used breakpoints of 1200 (theme tour) and 992 (nav menu collapse)
@@ -32,6 +46,13 @@ export const useLayoutStore = defineStore('layout', {
     },
     setSidebarCollapsed(value: boolean) {
       this.sidebarCollapsed = value;
+      if (typeof window === 'undefined') return;
+      try {
+        window.localStorage.setItem(SIDEBAR_COLLAPSED_KEY, value ? '1' : '0');
+      } catch {
+        // localStorage unavailable (private mode, disabled site data, ...) —
+        // collapse state just won't persist across reloads.
+      }
     },
   },
 });