Add 4x SAC cascade to model card

Add SAC cascade final 4x

Add model card

Keep only best cascade (SAC, 31.28 dB)

Add CAS cascade final (PSNR 30.50)

Add ACS cascade final (PSNR 29.78)

Add CSA cascade final (PSNR 30.53)

Add ASC cascade final (PSNR 30.02)

Add SCA cascade final (PSNR 30.41)

Add SAC cascade final (PSNR 31.28)

Add single-view baseline: SUNet sagittal 8x

Add single-view baseline: SUNet coronal 8x

Add single-view baseline: SUNet axial 8x

Add VSSR stage 3 (coronal) weights

Add VSSR stage 2 (axial) weights

Add VSSR stage 1 (sagittal) weights

initial commit