Escape issue summary in search response

[g4mm4-VCF]

Summary

In pages/search.php, the issue summary is concatenated directly into the HTML payload returned in the JSON data field, then injected into the DOM by the client-side JS via $.fn.after() on bug_report_page.php. Because that path parses HTML, any markup-special character in a stored summary is reflected to anyone running the plugin's live search.

This patch pipes the summary through string_display_line(), which is MantisBT's standard helper for HTML-safe single-line output. The bug id is also cast to int defensively.

Change

- '">' . $t_issue->id . ": " . $t_issue->summary . '</a></li>';
+ '">' . (int)$t_issue->id . ": "
+     . string_display_line( $t_issue->summary ) . '</a></li>';

One line, no behaviour change for normal summaries, brings the plugin in line with MantisBT core's output-escaping convention. string_display_line() also fires the EVENT_DISPLAY_TEXT hook, so installed formatting plugins (e.g. MantisCoreFormatting) still get to do their own processing.

Test plan

• Existing search behaviour unchanged for summaries that contain only plain text.
• Summaries that contain <, >, &, etc. are rendered as text in the dropdown rather than parsed as markup.
• Bug-id link still works (cast to int is a no-op for normal DB values).

Happy to coordinate further on a security advisory / release tag if useful.