Quick-win fixes from second review

- create_ticket_api.php: validate status (against TICKET_STATUSES) and
  priority (numeric 1-5). A non-numeric priority previously cast to 0 and
  escalated the ticket below P1 on the dedup/update path.
- manage_workflows.php: reject empty/invalid from_status/to_status on POST
  and PUT (must be valid ticket statuses) so the workflow table can't be
  populated with bogus transitions.
- TicketModel::getAllTickets: COUNT(*) OVER() rides on returned rows, so a
  page past the last row returned total/pages = 0. Fall back to a direct
  COUNT when an over-range page yields no rows, keeping pager math correct.
- DashboardView: stop double-escaping category/type/assigned active-filter
  labels (they were htmlspecialchars'd into the label and again at output,
  rendering R&D as R&D); output escaping is retained.
- check_duplicates.php / NotificationHelper::notifyWatchers: wrap the DB
  lookups in try/catch so a failed prepare/query degrades gracefully
  (advisory dup-check returns none; best-effort watcher notify is skipped)
  instead of fataling the request. Works whether mysqli throws or returns
  false. (manage_* endpoints already have a top-level try/catch.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

api/manage_workflows.php

@@ -82,6 +82,15 @@ try {
         case 'POST':
             $data = json_decode(file_get_contents('php://input'), true);
 
+            $wfValid = $GLOBALS['config']['TICKET_STATUSES'] ?? ['Open', 'Pending', 'In Progress', 'Closed'];
+            if (
+                !in_array($data['from_status'] ?? '', $wfValid, true)
+                || !in_array($data['to_status'] ?? '', $wfValid, true)
+            ) {
+                http_response_code(400);
+                echo json_encode(['success' => false, 'error' => 'from_status and to_status must be valid ticket statuses']);
+                exit;
+            }
             if (($data['from_status'] ?? '') === ($data['to_status'] ?? '')) {
                 http_response_code(400);
                 echo json_encode(['success' => false, 'error' => 'From Status and To Status cannot be the same']);
@@ -125,6 +134,15 @@ try {
 
             $data = json_decode(file_get_contents('php://input'), true);
 
+            $wfValid = $GLOBALS['config']['TICKET_STATUSES'] ?? ['Open', 'Pending', 'In Progress', 'Closed'];
+            if (
+                !in_array($data['from_status'] ?? '', $wfValid, true)
+                || !in_array($data['to_status'] ?? '', $wfValid, true)
+            ) {
+                http_response_code(400);
+                echo json_encode(['success' => false, 'error' => 'from_status and to_status must be valid ticket statuses']);
+                exit;
+            }
             if (($data['from_status'] ?? '') === ($data['to_status'] ?? '')) {
                 http_response_code(400);
                 echo json_encode(['success' => false, 'error' => 'From Status and To Status cannot be the same']);