v0.1.31

• NIfTI session loading improvements
  • 4D NIfTI Volume Support: Added comprehensive support for 4D NIfTI volumes with per-volume indexing
    • 4D volumes are now automatically detected and expanded into separate DataFrame rows for each 3D volume
    • Added Volume_Index field to track individual volumes within 4D data
    • Added NIfTI_Path_Display field showing volume-specific paths (e.g., file.nii.gz[0])
  • Enhanced Acquisition Field Grouping: Made acquisition field grouping more robust
    • Now filters for existing columns before grouping
    • Falls back to 'acq' field when specified fields aren't available
    • Prevents errors when grouping fields don't exist in the DataFrame