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/check_duplicates.php

@@ -50,12 +50,24 @@ $sql = "SELECT ticket_id, title, status, priority, created_at
 
 $types = "ss" . $visFilter['types'];
 $params = array_merge([$searchTerm, $soundexTitle], $visFilter['params']);
-$stmt = $conn->prepare($sql);
-if (!empty($params)) {
-    $stmt->bind_param($types, ...$params);
+
+// Duplicate detection is advisory (it must not block ticket creation), so on any
+// DB error degrade gracefully to "no duplicates" rather than fataling the request.
+// mysqli may throw (default exception mode) or return false depending on config.
+try {
+    $stmt = $conn->prepare($sql);
+    if (!$stmt) {
+        throw new RuntimeException('prepare failed: ' . $conn->error);
+    }
+    if (!empty($params)) {
+        $stmt->bind_param($types, ...$params);
+    }
+    $stmt->execute();
+    $result = $stmt->get_result();
+} catch (Throwable $e) {
+    error_log('check_duplicates: ' . $e->getMessage());
+    ResponseHelper::success(['duplicates' => []]);
 }
-$stmt->execute();
-$result = $stmt->get_result();
 
 while ($row = $result->fetch_assoc()) {
     // Calculate similarity score