feat(admin): phase 1 — hash-router

AdminRouter wraps existing switchTab for deep-linking.

- frontend/js/admin/router.js (new, 102L): parse/navigate/current/on/off, recursion guard via _navigating flag

- admin.html: +1 <script> before admin.js

- admin.js: switchTab(btn, opts) + initAdminRouter IIFE for hashchange dispatch

Backward compat: all 21 onclick=switchTab(this) callsites continue working.

F5 / back / forward / deep-link verified.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/js/admin/admin.js

@@ -54,7 +54,7 @@
 
     /* ─── Tabs ─── */
     let questionsInited = false, testsInited = false, assignmentsInited = false, usersInited = false, sessionsInited = false, subjectsInited = false, permissionsInited = false, shopInited = false, gamInited = false, tplInited = false, simsInited = false, gamesInited = false, sublogInited = false;
-    function switchTab(btn) {
+    function switchTab(btn, opts) {
       if (btn.classList.contains('locked')) {
         LS.toast('Этот раздел доступен только администраторам', 'warn');
         return;
@@ -77,6 +77,12 @@
       if (name === 'sims'        && !simsInited)        { simsInited = true;         loadSimsAdmin(); }
       if (name === 'games'       && !gamesInited)       { gamesInited = true;        loadGamesAdmin(); loadFsFeatures(); }
       if (name === 'sublog'      && !sublogInited)      { sublogInited = true;       loadSubmissionLog(); }
+      // Sync URL hash. `silent: true` only suppresses the router's own emit;
+      // a subsequent hashchange event will not re-fire switchTab thanks to
+      // the router's _navigating guard.
+      if (!(opts && opts.fromRouter) && window.AdminRouter) {
+        AdminRouter.navigate('#' + name, { silent: true });
+      }
     }
 
     /* Переход к вопросам конкретного предмета с открытием формы */
@@ -3546,3 +3552,40 @@
     loadStats();
     loadAvatarRequests(); // load badge count on page open
     if (window.lucide) lucide.createIcons();
+
+    /* ─── Hash router wiring ─── */
+    (function initAdminRouter() {
+      if (!window.AdminRouter) return;
+
+      function activate(route, opts) {
+        const name = route || 'stats';
+        const btn = document.querySelector('.admin-nav-item[data-tab="' + name + '"]');
+        if (!btn) {
+          console.warn('AdminRouter: unknown route', name);
+          AdminRouter.navigate('#stats', { replace: true, silent: true });
+          const fallback = document.querySelector('.admin-nav-item[data-tab="stats"]');
+          if (fallback) switchTab(fallback, { fromRouter: true });
+          return;
+        }
+        // Skip locked tabs (non-admin clicked an admin-only deep-link).
+        if (btn.classList.contains('locked')) {
+          LS.toast('Этот раздел доступен только администраторам', 'warn');
+          AdminRouter.navigate('#stats', { replace: true, silent: true });
+          const fallback = document.querySelector('.admin-nav-item[data-tab="stats"]');
+          if (fallback) switchTab(fallback, { fromRouter: true });
+          return;
+        }
+        switchTab(btn, { fromRouter: true });
+      }
+
+      AdminRouter.on('change', (r) => activate(r.route));
+
+      // Initial dispatch: respect existing hash, else default to #stats.
+      const initial = AdminRouter.current();
+      if (!initial.route) {
+        AdminRouter.navigate('#stats', { replace: true, silent: true });
+        // #stats tab-pane is already .active in markup; no switchTab needed.
+      } else if (initial.route !== 'stats') {
+        activate(initial.route);
+      }
+    })();