feat(avatars): 27 готовых пресет-аватаров + UI выбора для всех ролей

- backend/uploads/avatars/preset_01..27.png — иллюстрированные персонажи
- POST /api/avatar/preset — мгновенная установка без модерации
- GET  /api/avatar/presets — список доступных пресетов
- profile.html: галерея пресетов в модалке аватара, доступна студенту/учителю/админу
- кастомная загрузка с модерацией остаётся только для студентов

frontend/profile.html

@@ -718,6 +718,48 @@
     }
     .av-btn-send:hover { opacity: 0.88; }
     .av-btn-send:disabled { opacity: 0.45; cursor: not-allowed; }
+    /* Preset gallery */
+    .av-preset-hd {
+      width: 100%; display: flex; align-items: center; gap: 10px;
+      font-size: 0.74rem; font-weight: 700; color: rgba(255,255,255,0.55);
+      letter-spacing: 0.04em; text-transform: uppercase;
+    }
+    .av-preset-hd::before, .av-preset-hd::after {
+      content: ''; flex: 1; height: 1px; background: rgba(255,255,255,0.08);
+    }
+    .av-preset-grid {
+      width: 100%;
+      display: grid; grid-template-columns: repeat(6, 1fr); gap: 8px;
+      max-height: 220px; overflow-y: auto;
+      padding: 4px; box-sizing: border-box;
+      scrollbar-width: thin; scrollbar-color: rgba(155,93,229,0.4) transparent;
+    }
+    .av-preset-grid::-webkit-scrollbar { width: 6px; }
+    .av-preset-grid::-webkit-scrollbar-thumb { background: rgba(155,93,229,0.4); border-radius: 99px; }
+    .av-preset {
+      aspect-ratio: 1/1; border-radius: 12px; overflow: hidden;
+      border: 2px solid transparent; cursor: pointer;
+      background: rgba(255,255,255,0.04);
+      transition: transform .15s, border-color .15s, box-shadow .15s;
+      padding: 0;
+    }
+    .av-preset img { width: 100%; height: 100%; object-fit: cover; display: block; }
+    .av-preset:hover {
+      transform: scale(1.06); border-color: rgba(155,93,229,0.5);
+      box-shadow: 0 4px 14px rgba(155,93,229,0.25);
+    }
+    .av-preset.active {
+      border-color: var(--violet);
+      box-shadow: 0 0 0 2px rgba(155,93,229,0.3), 0 4px 14px rgba(155,93,229,0.4);
+    }
+    .av-or {
+      width: 100%; display: flex; align-items: center; gap: 10px;
+      font-size: 0.7rem; font-weight: 600; color: rgba(255,255,255,0.35);
+      letter-spacing: 0.04em;
+    }
+    .av-or::before, .av-or::after {
+      content: ''; flex: 1; height: 1px; background: rgba(255,255,255,0.06);
+    }
   </style>
   <script src="https://cdn.jsdelivr.net/npm/lucide@0.469.0/dist/umd/lucide.min.js"></script>
 </head>
@@ -1228,11 +1270,11 @@
         avatarEl.textContent = initials;
       }
 
-      // Show edit button for students only
-      if (u.role === 'student') {
-        document.getElementById('p-avatar-edit-btn').style.display = 'flex';
-        loadAvatarStatus();
-      }
+      // Show edit button for all roles
+      document.getElementById('p-avatar-edit-btn').style.display = 'flex';
+      // Upload-with-moderation only for students; admin/teacher use presets directly
+      window._lsRole = u.role;
+      if (u.role === 'student') loadAvatarStatus();
 
       document.getElementById('profile-name').textContent = u.name||'—';
       document.getElementById('profile-email').textContent= u.email||'—';
@@ -1864,11 +1906,72 @@
     // Show delete btn only if has actual avatar
     document.getElementById('av-del-btn').classList.toggle('visible', !!img);
 
-    avLoadStatus();
+    // Show upload section only for students (moderation)
+    document.getElementById('av-upload-block').style.display =
+      (window._lsRole === 'student') ? 'flex' : 'none';
+
+    avLoadPresets();
+    if (window._lsRole === 'student') avLoadStatus();
     modal.classList.add('open');
     if (LS.sfx) LS.sfx.play('modal_open');
   }
 
+  /* ── Load preset grid ── */
+  let _avPresetsCache = null;
+  async function avLoadPresets() {
+    const grid = document.getElementById('av-preset-grid');
+    if (!_avPresetsCache) {
+      try {
+        const data = await LS.get('/api/avatar/presets');
+        _avPresetsCache = data.presets || [];
+      } catch { _avPresetsCache = []; }
+    }
+    // Find current avatar filename to mark as active
+    const bigAv = document.getElementById('big-avatar');
+    const img   = bigAv.querySelector('img');
+    const curSrc = img ? img.src : '';
+    const curFile = curSrc.split('/').pop().split('?')[0];
+
+    grid.innerHTML = _avPresetsCache.map(f => `
+      <button class="av-preset${f === curFile ? ' active' : ''}" data-file="${LS.escapeHtml(f)}"
+              onclick="avPickPreset('${LS.escapeHtml(f)}', this)" title="Выбрать аватар">
+        <img src="/avatars/${LS.escapeHtml(f)}" alt="" loading="lazy">
+      </button>
+    `).join('');
+  }
+
+  /* ── Pick preset ── */
+  async function avPickPreset(filename, btn) {
+    if (btn.disabled) return;
+    btn.disabled = true;
+    try {
+      await LS.post('/api/avatar/preset', { filename });
+      const url = '/avatars/' + filename + '?t=' + Date.now();
+
+      // Update left-panel avatar
+      document.getElementById('big-avatar').innerHTML =
+        `<img src="${url}" alt="Аватар">`;
+      // Reset student status badge
+      document.getElementById('p-avatar-status').className = 'p-avatar-status';
+      // Update modal preview
+      document.getElementById('av-modal-cur').innerHTML =
+        `<img src="${url}" alt="Аватар">`;
+      document.getElementById('av-modal-status').className = 'av-status-row';
+      document.getElementById('av-del-btn').classList.add('visible');
+
+      // Mark active
+      document.querySelectorAll('.av-preset').forEach(b => b.classList.remove('active'));
+      btn.classList.add('active');
+
+      LS.toast('Аватар обновлён', 'success');
+      if (LS.sfx) LS.sfx.play('success');
+    } catch (e) {
+      LS.toast(e.message || 'Ошибка', 'error');
+    } finally {
+      btn.disabled = false;
+    }
+  }
+
   function avClose() {
     document.getElementById('av-modal').classList.remove('open');
     avBack();
@@ -2180,20 +2283,27 @@
       <!-- Status (pending / rejected) -->
       <div class="av-status-row" id="av-modal-status"></div>
 
-      <!-- Drop zone -->
-      <div class="av-drop" id="av-drop"
-           ondragover="avDragOver(event)" ondragleave="avDragLeave(event)" ondrop="avDrop(event)"
-           onclick="document.getElementById('av-file-inp').click()" role="button" tabindex="0"
-           onkeydown="if(event.key==='Enter'||event.key===' ')this.click()">
-        <svg class="av-drop-icon" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round">
-          <path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"/>
-          <polyline points="17 8 12 3 7 8"/>
-          <line x1="12" y1="3" x2="12" y2="15"/>
-        </svg>
-        <div class="av-drop-txt">Перетащите фото или нажмите для выбора</div>
-        <div class="av-drop-sub">PNG, JPG, WebP · до 2 МБ</div>
-        <input type="file" id="av-file-inp" accept="image/png,image/jpeg,image/webp"
-               style="display:none" onchange="avFileChosen(this)">
+      <!-- Preset gallery -->
+      <div class="av-preset-hd">Готовые аватары</div>
+      <div class="av-preset-grid" id="av-preset-grid"></div>
+
+      <!-- Custom upload (student only) -->
+      <div id="av-upload-block" style="width:100%;display:none;flex-direction:column;align-items:center;gap:14px">
+        <div class="av-or">или загрузите своё</div>
+        <div class="av-drop" id="av-drop"
+             ondragover="avDragOver(event)" ondragleave="avDragLeave(event)" ondrop="avDrop(event)"
+             onclick="document.getElementById('av-file-inp').click()" role="button" tabindex="0"
+             onkeydown="if(event.key==='Enter'||event.key===' ')this.click()">
+          <svg class="av-drop-icon" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round">
+            <path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"/>
+            <polyline points="17 8 12 3 7 8"/>
+            <line x1="12" y1="3" x2="12" y2="15"/>
+          </svg>
+          <div class="av-drop-txt">Перетащите фото или нажмите для выбора</div>
+          <div class="av-drop-sub">PNG, JPG, WebP · до 2 МБ · с модерацией</div>
+          <input type="file" id="av-file-inp" accept="image/png,image/jpeg,image/webp"
+                 style="display:none" onchange="avFileChosen(this)">
+        </div>
       </div>
 
       <!-- Delete current avatar -->