feat(admin): sortable columns for active users table

All 6 columns clickable: # and numeric columns default desc,
name defaults asc, last login sorts by date value.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

templates/admin/user_activity.html

@@ -355,26 +355,26 @@
         <h2>Najbardziej aktywni uzytkownicy</h2>
         {% if active_users %}
         <div class="table-scroll">
-            <table class="data-table">
+            <table class="data-table" id="active-users-table">
                 <thead>
                     <tr>
-                        <th>#</th>
-                        <th>Uzytkownik</th>
-                        <th>Sesje</th>
-                        <th>Laczny czas (min)</th>
-                        <th>Odslony</th>
-                        <th>Ostatnie logowanie</th>
+                        <th class="sortable" data-col="0" data-type="number">#</th>
+                        <th class="sortable" data-col="1" data-type="string">Użytkownik</th>
+                        <th class="sortable sort-desc" data-col="2" data-type="number">Sesje</th>
+                        <th class="sortable" data-col="3" data-type="number">Łączny czas (min)</th>
+                        <th class="sortable" data-col="4" data-type="number">Odsłony</th>
+                        <th class="sortable" data-col="5" data-type="date">Ostatnie logowanie</th>
                     </tr>
                 </thead>
                 <tbody>
                     {% for u in active_users %}
                     <tr>
-                        <td>{{ loop.index }}</td>
+                        <td class="num">{{ loop.index }}</td>
                         <td>{{ u.name }}</td>
                         <td class="num">{{ u.session_count }}</td>
                         <td class="num">{{ u.total_time_min }}</td>
                         <td class="num">{{ u.total_pages }}</td>
-                        <td>{{ u.last_login.strftime('%d.%m.%Y %H:%M') if u.last_login else '-' }}</td>
+                        <td data-sort-value="{{ u.last_login.strftime('%Y%m%d%H%M') if u.last_login else '0' }}">{{ u.last_login.strftime('%d.%m.%Y %H:%M') if u.last_login else '-' }}</td>
                     </tr>
                     {% endfor %}
                 </tbody>
@@ -510,4 +510,42 @@
         });
     });
 })();
+
+/* --- Active users table: sorting --- */
+(function() {
+    var table = document.getElementById('active-users-table');
+    if (!table) return;
+    var tbody = table.querySelector('tbody');
+    var rows = Array.from(tbody.querySelectorAll('tr'));
+
+    table.querySelectorAll('th.sortable').forEach(function(th) {
+        th.addEventListener('click', function() {
+            var col = parseInt(th.dataset.col);
+            var type = th.dataset.type;
+            var isDesc = th.classList.contains('sort-desc');
+            var dir = isDesc ? 1 : -1;
+
+            table.querySelectorAll('th.sortable').forEach(function(h) {
+                h.classList.remove('sort-asc', 'sort-desc');
+            });
+            th.classList.add(isDesc ? 'sort-asc' : 'sort-desc');
+
+            rows.sort(function(a, b) {
+                var aCell = a.cells[col], bCell = b.cells[col];
+                if (type === 'date') {
+                    var av = aCell.dataset.sortValue || '0';
+                    var bv = bCell.dataset.sortValue || '0';
+                    return av < bv ? dir : av > bv ? -dir : 0;
+                } else if (type === 'number') {
+                    return (parseFloat(aCell.textContent) - parseFloat(bCell.textContent)) * dir;
+                } else {
+                    var av = aCell.textContent.trim().toLowerCase();
+                    var bv = bCell.textContent.trim().toLowerCase();
+                    return av < bv ? dir : av > bv ? -dir : 0;
+                }
+            });
+            rows.forEach(function(r) { tbody.appendChild(r); });
+        });
+    });
+})();
 {% endblock %}