form: add Select All checkbox to products list in access request form

app/templates/login.html

@@ -139,7 +139,13 @@
         <input id="am-manager" type="text" placeholder="Если известно — укажите имя" />
       </div>
       <div class="access-field">
-        <label>Интересующие продукты</label>
+        <label style="display:flex;align-items:center;justify-content:space-between">
+          Интересующие продукты
+          <label id="am-select-all-wrap" style="display:none;font-weight:400;font-size:13px;cursor:pointer;gap:6px;align-items:center">
+            <input type="checkbox" id="am-select-all" style="cursor:pointer" />
+            <span>Выбрать все</span>
+          </label>
+        </label>
         <div id="am-products" class="access-products-wrap">
           <div class="access-products-loading">Загрузка...</div>
         </div>
@@ -186,6 +192,7 @@
     } else {
       ['am-name','am-company','am-email','am-phone','am-manager'].forEach(function(id){ var el=document.getElementById(id); if(el){el.value='';el.classList.remove('am-invalid');} });
       document.querySelectorAll('#am-products input[type=checkbox]').forEach(function(cb){ cb.checked=false; });
+      var saBox = document.getElementById('am-select-all'); if (saBox) saBox.checked = false;
       var err=document.getElementById('am-error'); if(err) err.style.display='none';
       var btn=document.getElementById('am-submit'); if(btn){btn.disabled=false;btn.textContent='Запросить доступ';}
     }
@@ -225,6 +232,21 @@
         wrap.appendChild(group);
       }
       productsLoaded = true;
+      // Show "select all" checkbox
+      const saWrap = document.getElementById('am-select-all-wrap');
+      if (saWrap) saWrap.style.display = 'flex';
+      const saBox = document.getElementById('am-select-all');
+      if (saBox) {
+        saBox.addEventListener('change', function() {
+          document.querySelectorAll('#am-products input[type=checkbox]').forEach(function(cb){ cb.checked = saBox.checked; });
+        });
+        // Keep "select all" in sync when individual boxes change
+        wrap.addEventListener('change', function(e) {
+          if (e.target === saBox) return;
+          const all = [...document.querySelectorAll('#am-products input[type=checkbox]')];
+          saBox.checked = all.length > 0 && all.every(function(cb){ return cb.checked; });
+        });
+      }
     } catch(e) {
       wrap.innerHTML = '<div class="access-products-loading">Не удалось загрузить список</div>';
     }