Fix ticket page 500 from unbounded audit timeline (#112)

A ticket updated by hwmonDaemon had ~52k audit rows; getTicketTimeline()
loaded all of them and exhausted PHP's 128MB memory limit, so the ticket
page returned 500. Not related to the MCP server.

- getTicketTimeline() takes a limit (newest first). The ticket page shows
  the latest 500 events with a note when older ones are omitted; the JSON
  export caps at 5000.
- create_ticket_api.php: the description is refreshed on every run, and
  that alone wrote a reason-only audit row every few minutes per open
  ticket. Audit only real title/priority changes.
- create_ticket_api.php: after creating a brand-new ticket the dedup retry
  loop fell through into a second iteration on a closed connection,
  appending a 500 error body after the success response. Exit instead.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MGDKHiU5RJdo3dqQUDow3X

models/AuditLogModel.php

@@ -561,20 +561,27 @@ class AuditLogModel
      * Get formatted timeline for a specific ticket
      * Includes all ticket updates and comments
      *
+     * Returns only the newest $limit events: a ticket touched by an automated
+     * reporter can accumulate tens of thousands of rows, and loading them all
+     * exhausted PHP memory on the ticket page (tinker_tickets#112).
+     *
      * @param string $ticketId Ticket ID
+     * @param int $limit Maximum number of events (newest first)
      * @return array Timeline events
      */
-    public function getTicketTimeline($ticketId)
+    public function getTicketTimeline($ticketId, $limit = self::DEFAULT_LIMIT)
     {
+        $limit = $this->validateLimit((int)$limit, self::EXPORT_LIMIT);
         $stmt = $this->conn->prepare(
             "SELECT al.*, u.username, u.display_name
              FROM audit_log al
              LEFT JOIN users u ON al.user_id = u.user_id
              WHERE (al.entity_type = 'ticket' AND al.entity_id = ?)
                 OR (al.entity_type = 'comment' AND JSON_UNQUOTE(JSON_EXTRACT(al.details, '$.ticket_id')) = ?)
-             ORDER BY al.created_at DESC"
+             ORDER BY al.created_at DESC, al.audit_id DESC
+             LIMIT ?"
         );
-        $stmt->bind_param("ss", $ticketId, $ticketId);
+        $stmt->bind_param("ssi", $ticketId, $ticketId, $limit);
         $stmt->execute();
         $result = $stmt->get_result();