[TASK] Implement drop old versions endpoint

[hassandotcms]

Description

Implement DELETE /v1/maintenance/_oldVersions in MaintenanceResource.java. Deletes all versions of versionable objects (Contentlets, Containers, Templates, Links, Workflow History) older than a specified date.

Acceptance Criteria

• API caller must provide a date query parameter in MM/dd/yyyy format
• Endpoint must call CMSMaintenanceFactory.deleteOldAssetVersions(date)
• API caller must receive the count of deleted records in response
• API caller must receive a success indicator (deletedCount >= 0 means success, -1 means error)
• Must require CMS Administrator role and Maintenance portlet access
• API caller must receive 400 Bad Request if date is missing or invalid

Priority

None

Additional Context

• CMSMaintenanceFactory.deleteOldAssetVersions() iterates in 30-day chunks from the oldest inode date to the specified date, each chunk in a Hibernate transaction
• Deletes via: DropOldContentletRunner (contentlets), ContainerAPI.deleteOldVersions(), TemplateAPI.deleteOldVersions(), MenuLinkAPI.deleteOldVersions(), WorkflowAPI.deleteWorkflowHistoryOldVersions()
• Flushes all caches when totalRecords > 0
• Can take minutes on large datasets
• DWR legacy: CMSMaintenanceAjax.removeOldVersions(date) line 260