[FEATURE] Log File Listing API

Problem

The log file dropdown (for selecting which file to tail or download) is currently populated by a JSP scriptlet in tail_log.jsp that reads the filesystem at page load. All other log functionality (tailing via SSE, downloading, logger management) already has REST coverage. Need a REST endpoint to answer "What logs can I view?"

Goal

Provide a REST endpoint that returns the list of available log files, matching the same directory and regex filter configuration used by the existing tail and download endpoints.

APIs

• GET /v1/maintenance/_logFiles — List available log files for tailing/download

Personas

• Developer Teams — Need REST API for Angular Log Files tab dropdown
• System Administrators — Need to discover available log files before tailing/downloading

Legacy Reference

• JSP: tail_log.jsp lines 36–57 (file listing scriptlet)
• Config: TAIL_LOG_LOG_FOLDER (default ./dotsecure/logs/), TAIL_LOG_FILE_REGEX (default .*)
• Related existing endpoints: GET /v1/logs/{fileName}/_tail, GET /v1/maintenance/_downloadLog/{fileName}
• Target Class: MaintenanceResource.java (/api/v1/maintenance)

Start in MaintenanceResource.java under /api/v1/maintenance, then compare the file-listing logic in tail_log.jsp lines 36–57 with the existing tail and download endpoints. Verify the TAIL_LOG_LOG_FOLDER and TAIL_LOG_FILE_REGEX configuration, and consider the work complete when GET /v1/maintenance/_logFiles returns the matching available log files for the Angular dropdown.