Migrate UI to Lucide icons, reorder sidebar, and polish journal/groups UX

- Replace emoji icons with Lucide across admin pages; add vendor/lucide.min.js and renderIcons() helper\n- Reorder sidebar logically (Dashboard, Journal, Students, Groups, Files, Links, Trash + admin sections)\n- Groups: open photo chronology only via the Фото button; covers no longer clickable\n- Journal: show group badge over card photo, compact AI-status icon beside description, and date range in empty-state message\n- Update README (AI worker, Lucide, worker.js)

public/js/dashboard.js

@@ -57,7 +57,7 @@ function renderRecent(rows) {
     <div class="recent-item">
       ${e.photo_path
         ? `<img src="${API}${e.photo_path}" data-img="${API}${e.photo_path}" alt="">`
-        : `<div class="thumb">🎓</div>`}
+        : `<div class="thumb"><i data-lucide="graduation-cap"></i></div>`}
       <div class="r-info">
         <div class="r-name">${esc(e.student_name)}</div>
         <div class="r-meta">${esc(e.group_name)} · ${new Date(e.created_at).toLocaleString('ru', { day: '2-digit', month: '2-digit', hour: '2-digit', minute: '2-digit' })}</div>
@@ -110,6 +110,7 @@ async function loadDashboard() {
   renderActive(d.active_groups);
   renderTop(d.top_students);
   renderPhotos(d.photos);
+  renderIcons();
 }
 
 document.getElementById('imgModal').addEventListener('click', e => e.currentTarget.classList.remove('open'));