UX and architecture fixes: bulk-delete, template guard, statuses config

Bug fixes:
- bulk-delete action called undefined bulkDelete() — wired to the
  existing showBulkDeleteModal() so the confirmation modal actually shows

UX:
- Template loader now checks for existing title/description and asks
  for confirmation before overwriting user-typed content
- Visibility select shows a dynamic hint paragraph that updates when
  the user changes the selection (public/internal/confidential)

Architecture:
- TICKET_STATUSES added to config as single source of truth; all
  hardcoded ['Open','Pending','In Progress','Closed'] arrays in
  DashboardView now read from config; bulk-status modal in dashboard.js
  reads window.TICKET_STATUSES (set from PHP) with array fallback
- ASSET_VERSION now auto-computed from max mtime of dashboard/ticket
  CSS+JS files so browsers always pick up changes on deploy; manual
  override still available via ASSET_VERSION in .env
- Removed 10 dead standalone stat methods from StatsModel (getOpenTicketCount,
  getClosedTicketCount, getTicketsByPriority, etc.) — all superseded by
  the consolidated fetchAllStats() queries, never called externally

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

assets/js/dashboard.js

@@ -130,7 +130,7 @@ document.addEventListener('DOMContentLoaded', function() {
                 if (typeof showBulkPriorityModal === 'function') showBulkPriorityModal();
                 break;
             case 'bulk-delete':
-                if (typeof bulkDelete === 'function') bulkDelete();
+                showBulkDeleteModal();
                 break;
             case 'clear-selection':
                 clearSelection();
@@ -760,10 +760,7 @@ function showBulkStatusModal() {
                     <label for="bulkStatus">New Status:</label>
                     <select id="bulkStatus" class="lt-select">
                         <option value="">Select Status...</option>
-                        <option value="Open">Open</option>
-                        <option value="Pending">Pending</option>
-                        <option value="In Progress">In Progress</option>
-                        <option value="Closed">Closed</option>
+                        ${(window.TICKET_STATUSES || ['Open','Pending','In Progress','Closed']).map(s => `<option value="${s}">${s}</option>`).join('')}
                     </select>
                 </div>
                 <div class="lt-modal-footer">