[FEATURE] Quartz System Jobs APIs

Problem

Quartz scheduler job management (listing system jobs with trigger details, deleting errored jobs) is currently only accessible via JSP scriptlets in system_jobs.jsp and Struts form actions. Need REST endpoints to answer "What system jobs are scheduled?"

Note: These are Quartz scheduler jobs (org.quartz.Job/StatefulJob), NOT the newer JobQueueManagerAPI jobs exposed at /api/v1/jobs. Quartz jobs include system infrastructure tasks like ServerHeartbeatJob, BinaryCleanupJob, DropOldContentVersionsJob, AccessTokenRenewJob, etc.

Goal

Provide REST endpoints for listing all Quartz scheduler jobs with trigger details and deleting errored/orphaned jobs.

APIs

• GET /v1/maintenance/_systemJobs — List all Quartz scheduler jobs
• DELETE /v1/maintenance/_systemJobs/{group}/{name} — Delete a Quartz job

Personas

• Developer Teams — Need REST APIs for Angular System Jobs tab
• System Administrators — Need to monitor scheduled tasks and clean up broken jobs after upgrades

Legacy Reference

• JSP: system_jobs.jsp lines 39–108 (job listing with Quartz API calls)
• Struts Action: ViewCMSMaintenanceAction._deleteScheduler() lines 282–289
• Quartz Utils: com.dotmarketing.quartz.QuartzUtils — getScheduler(), isJobRunning(), removeJob()
• Target Class: MaintenanceResource.java (/api/v1/maintenance)

Start with MaintenanceResource.java and compare the Quartz logic in system_jobs.jsp lines 39–108 with ViewCMSMaintenanceAction._deleteScheduler() lines 282–289. Read QuartzUtils.getScheduler(), isJobRunning(), and removeJob() to understand the existing operations. Done means the two maintenance endpoints list Quartz jobs with trigger details and delete a specified Quartz job.