Simulate realistic gradient waveforms from scanner-measured GIRFs.

[alyakurt]

Feature Request

KomaMRI currently supports only ideal gradient waveforms. Add a gradient-system model that uses scanner-measured gradient impulse response functions (GIRFs).

The model should be able to:

• Apply measured GIRFs to commanded EPI and spiral gradient waveforms.
• Simulate the resulting artifacts in the forward signal and direct reconstruction.
• Compensate for these artifacts by using the GIRF-derived trajectory during reconstruction for better image quality.
• Preserve ideal-gradient behavior by default.