Feature Request: Automatic Child VHDX Cleanup in Profile Disks

SUMMARY
Profile Unity Client should include automatic cleanup logic for orphaned child VHDX files to prevent Profile Disk space expansion from incomplete logoffs and stale sessions.

PROBLEM STATEMENT
When Profile Disks experience incomplete logoffs or stale sessions, child VHDX files accumulate on the storage backend and are not automatically cleaned up. Over time, this leads to:
  - Unnecessary disk space consumption
  - Potential performance degradation
  - Manual intervention required for cleanup
  - Risk of storage exhaustion

PROPOSED SOLUTION
Implement automatic child VHDX cleanup logic within the Profile Unity Client that executes during both launch and exit events.

CLEANUP LOGIC REQUIREMENTS:

1. Discovery Phase
   - Identify parent VHDX file for the current user
   - Enumerate all associated child VHDX files

2. Safety Checks
   - Count total child VHDX files
   - Only proceed if child count exceeds threshold (more than 2 children)

3. Selection Process
   - Sort child VHDXs by creation/modification timestamp
   - Identify oldest child VHDX file

4. Validation
   - Test if oldest child VHDX is locked/in use
   - Verify file handle status before deletion

5. Cleanup Action
   - Delete oldest child VHDX only if not in use
   - Skip deletion if file is locked (safety first)

6. Logging and Reporting
   - Log all cleanup attempts (success and failure)
   - Record deleted file names, sizes, and timestamps
   - Report errors for administrator review

BENEFITS
  - Automated maintenance reduces administrative overhead
  - Prevents storage space issues proactively
  - Self-healing mechanism for common profile disk issues
  - Maintains system health without user intervention

ADDITIONAL CONSIDERATIONS
  - Configurable threshold for minimum child count before cleanup
  - Optional administrator notification for cleanup actions
  - Configurable retention policy (age-based vs. count-based)
  - Integration with existing Profile Unity logging infrastructure