DO NOT SQUASH: Simple accurate vp output

[Olender]

TLDR: New method to export scalar fields to segy or png and some io file reorganization

Since we use high-order FEM we cant visualize correctly in paraview. I've introduced a new utility function for exporting scalar fields to segy or png (for paper or report images). Now we can export our data to a more accurate (based on the grid space of the desired sampling) image. Unfortunately, since the parallelism related decorators were all over the place I had to reorganize them as well.

Therefore, this pull request refactors the spyro/io module to improve code organization. I just moved the parallelism-related decorators and functions into a new parallelism_wrappers module, and updated the imports throughout the codebase. These changes help separate concerns between basic I/O operations and parallelism logic.

Refactoring and Code Organization

• Moved all parallelism-related decorators and utility functions (such as ensemble_save, ensemble_load, ensemble_gradient, ensemble_functional, delete_tmp_files, switch_serial_shot, ensemble_shot_record, is_owner, and ensemble_propagator) from basicio.py to a new parallelism_wrappers.py module, and updated imports accordingly throughout the codebase.

New Features

• Added a new utility function export_scalar_field in segy_io.py to export scalar fields to SEG-Y or PNG formats, including logic for intermediate conversion and file validation. (spyro/io/segy_io.py,

[codecov]

Codecov Report

❌ Patch coverage is 74.77064% with 55 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.63%. Comparing base (05b166a) to head (d87e538).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
spyro/io/parallelism_wrappers.py	75.91%	46 Missing ⚠️
spyro/io/segy_io.py	35.71%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #330      +/-   ##
==========================================
- Coverage   84.73%   84.63%   -0.11%     
==========================================
  Files          97       98       +1     
  Lines        9379     9409      +30     
==========================================
+ Hits         7947     7963      +16     
- Misses       1432     1446      +14     

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