Exclude shared notify list and redact title in notifyWatchers() for non-public tickets (#71)

notifyWatchers() only redacted the comment/activity preview for
non-public tickets — the shared MATRIX_NOTIFY_USERS list was still
merged into notify_users unconditionally, and the ticket title was
never redacted at all. A status-change/comment notification for a
confidential ticket with watchers still broadcast that ticket's title
to the shared list, even though the function's own docblock intended
to protect non-public tickets from it.

For non-public tickets, the shared list is now excluded entirely
(only actual watchers are notified) and the title is redacted via the
same redactedTitle() helper added for #46. Verified against real
MariaDB with a real watcher row: for a confidential ticket, the
captured webhook payload has only the watcher's Matrix ID (no shared
list) and a redacted title; for the same ticket made public, the
shared list is included and the title passes through unchanged.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015nCxwFFsy8ouMWzn56rPVP

helpers/NotificationHelper.php

@@ -189,11 +189,12 @@ class NotificationHelper
      * @param array       $extraData    Merged into the payload (old_status/new_status, author, etc.)
      * @param int|null    $excludeUserId  Don't notify the actor themselves
      * @param string      $visibility   Ticket visibility: 'public', 'internal', or
-     *                                   'confidential'. notify_users includes the
-     *                                   shared list, which may contain users without
-     *                                   access to non-public tickets, so any comment
-     *                                   body preview in $extraData is redacted for
-     *                                   non-public tickets.
+     *                                   'confidential'. The shared notify list may
+     *                                   contain users without access to non-public
+     *                                   tickets, so for those tickets it's excluded
+     *                                   entirely (only actual watchers are notified)
+     *                                   and both the title and any comment/body
+     *                                   preview in $extraData are redacted.
      */
     public static function notifyWatchers(\mysqli $conn, $ticketId, string $ticketTitle, string $event, array $extraData = [], ?int $excludeUserId = null, string $visibility = 'public'): void
     {
@@ -253,13 +254,17 @@ class NotificationHelper
             return;
         }
 
-        // Remove the global notify list duplicates and build payload
-        $allNotify = array_unique(array_merge($matrixIds, self::notifyUsers()));
+        // The shared notify list may include users without access to
+        // non-public tickets, so only mix it in for public tickets — for
+        // internal/confidential tickets, notify actual watchers only.
+        $allNotify = $visibility === 'public'
+            ? array_unique(array_merge($matrixIds, self::notifyUsers()))
+            : $matrixIds;
 
         $payload = array_merge($extraData, [
             'event'        => $event,
             'ticket_id'    => $ticketId,
-            'title'        => $ticketTitle,
+            'title'        => self::redactedTitle($ticketTitle, $visibility),
             'url'          => UrlHelper::ticketUrl($ticketId),
             'notify_users' => array_values($allNotify),
         ]);