feat: SLA live timer, notification bell, lt-toggle MD, right drawer, kanban drag-drop

- TicketView: SLA banner now shows live HH:MM:SS elapsed + countdown via JS setInterval
  (previously showed static hours from PHP)
- TicketView: Markdown toggles in comment form replaced with lt-toggle switches
- layout_header: In-app notification bell (🔔) with dropdown panel for all users
- layout_footer: Notification JS — polls /api/notifications.php every 60s, badge count,
  mark-all-read, panel open/close with Escape/outside-click
- api/notifications.php (new): Returns assign/comment/status-change events from audit_log
  for current user's tickets and watched tickets; mark-read via user_preferences
- DashboardView: Ticket preview right drawer — Ctrl+click title or ⊙ peek button
  opens lt-drawer-right with ticket summary extracted from table row DOM
- DashboardView: lt.sortable wired on all 4 kanban columns (group='kanban')
  Cross-column drag = status change via POST /api/update_ticket.php with optimistic UI

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/js/dashboard.js

@@ -1151,7 +1151,13 @@ function populateKanbanCards() {
         card.className = 'lt-kanban-card lt-kanban-card--p' + pNum;
         card.setAttribute('role', 'button');
         card.setAttribute('tabindex', '0');
-        card.onclick  = () => window.location.href = '/ticket/' + encodeURIComponent(ticketId);
+        card.dataset.ticketId = ticketId;
+        card.dataset.status   = status;
+        card.addEventListener('click', (e) => {
+            // Don't navigate if drag just ended (drag adds/removes is-dragging briefly)
+            if (card.dataset.dragged) { delete card.dataset.dragged; return; }
+            window.location.href = '/ticket/' + encodeURIComponent(ticketId);
+        });
         card.onkeydown = (e) => { if (e.key === 'Enter' || e.key === ' ') card.click(); };
         card.innerHTML =
             '<div class="lt-kanban-card-header">' +
@@ -1172,6 +1178,65 @@ function populateKanbanCards() {
         const s = el.dataset.status;
         el.textContent = '(' + (counts[s] || 0) + ')';
     });
+
+    // ── Kanban drag-and-drop via lt.sortable ──────────────────────
+    if (window.lt && lt.sortable) {
+        const colStatusMap = {
+            'kanban-col-open':       'Open',
+            'kanban-col-pending':    'Pending',
+            'kanban-col-inprogress': 'In Progress',
+            'kanban-col-closed':     'Closed',
+        };
+
+        function handleKanbanSort(newItems, movedCard) {
+            if (!movedCard) return;
+            const newColEl  = movedCard.parentNode;
+            const newColId  = newColEl ? newColEl.id : null;
+            const newStatus = colStatusMap[newColId];
+            const oldStatus = movedCard.dataset.status;
+            const ticketId  = movedCard.dataset.ticketId;
+
+            if (!newStatus || !ticketId || newStatus === oldStatus) return;
+
+            movedCard.dataset.status  = newStatus;
+            movedCard.dataset.dragged = '1';
+
+            // Optimistically update column counts
+            const dec = document.querySelector(`.column-count[data-status="${oldStatus}"]`);
+            const inc = document.querySelector(`.column-count[data-status="${newStatus}"]`);
+            if (dec) dec.textContent = '(' + Math.max(0, (parseInt(dec.textContent.replace(/\D/g,''),10)||1) - 1) + ')';
+            if (inc) inc.textContent = '(' + ((parseInt(inc.textContent.replace(/\D/g,''),10)||0) + 1) + ')';
+
+            // POST status update
+            fetch('/api/update_ticket.php', {
+                method: 'POST',
+                credentials: 'same-origin',
+                headers: { 'Content-Type': 'application/json', 'X-CSRF-Token': window.CSRF_TOKEN || '' },
+                body: JSON.stringify({ ticket_id: parseInt(ticketId, 10), status: newStatus })
+            })
+            .then(r => r.json())
+            .then(data => {
+                if (data.success) {
+                    lt.toast.success('Ticket #' + ticketId + ' → ' + newStatus, 2500);
+                    movedCard.dataset.status = newStatus;
+                } else {
+                    lt.toast.error('Status update failed: ' + (data.error || 'Unknown error'));
+                    // Revert: put card back in original column
+                    const origCol = document.getElementById(Object.keys(colStatusMap).find(k => colStatusMap[k] === oldStatus));
+                    if (origCol) origCol.appendChild(movedCard);
+                    movedCard.dataset.status = oldStatus;
+                }
+            })
+            .catch(() => {
+                lt.toast.error('Network error — status not saved');
+            });
+        }
+
+        Object.keys(columns).forEach(status => {
+            const col = columns[status];
+            if (col) lt.sortable.init(col, { group: 'kanban', onSort: handleKanbanSort });
+        });
+    }
 }
 
 // Restore view mode on page load — click the kanban tab button to trigger lt.tabs