[TASK] Implement fix assets endpoints

Description

Implement POST /v1/maintenance/_fixAssets and GET /v1/maintenance/_fixAssets in MaintenanceResource.java. POST starts the fix assets inconsistencies process which runs all registered FixTask classes. GET returns the current/last results for progress checking.

Acceptance Criteria

POST /v1/maintenance/_fixAssets

• Endpoint must call FixTasksExecutor.getInstance().execute(null) to run all registered fix tasks
• API caller must receive a list of task results, each containing: total, errorsFixed, initialTime, finalTime, description
• API caller must receive null/empty entity if no tasks were executed
• Must require CMS Administrator role and Maintenance portlet access

GET /v1/maintenance/_fixAssets

• API caller must receive the current task results from FixTasksExecutor.getInstance().getTasksresults()
• API caller must receive null/empty entity if no results exist
• Must require CMS Administrator role and Maintenance portlet access

Priority

None

Additional Context

• FixTasksExecutor.execute() is synchronous — blocks until all tasks complete. Results accumulate incrementally in returnValue as each task finishes
• Tasks loaded from TaskLocatorUtil.getFixTaskClasses(), sorted by name, each runs shouldRun() + executeFix() in Hibernate transactions
• GET is called on page load to recover results from a previous run
• DWR legacy: CMSMaintenanceAjax.fixAssetsInconsistencies() and getFixAssetsProgress()

Start in MaintenanceResource.java and inspect existing maintenance endpoints, then read FixTasksExecutor.execute(null) and getTasksresults() to understand their result behavior. Compare the legacy CMSMaintenanceAjax.fixAssetsInconsistencies() and getFixAssetsProgress() entry points. Done means both endpoints return the specified results or an empty entity and enforce CMS Administrator role and Maintenance portlet access.