Add grid-based sampling for scintillation spectra

[Rashika-Gupta]

Added support for grid-based inputs (energy, intensity) in ImportScintComponent Built CDFs from input spectra and stored them in ScintillationData Updated ScintillationGenerator to sample photons using either Gaussian or grid-based spectra Preserved backward compatibility with existing Gaussian-only inputs

[github-actions[bot]]

Test summary

  500 files    815 suites   12s :stopwatch: 1 318 tests 1 304 :white_check_mark: 14 :zzz: 0 :x: 2 662 runs  2 654 :white_check_mark:  8 :zzz: 0 :x:

Results for commit c1329ddc.

:recycle: This comment has been updated with latest results.

[codecov[bot]]

Codecov Report

:x: Patch coverage is 82.60870% with 16 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 84.88%. Comparing base (58dce7f) to head (341af6f). :warning: Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/celeritas/ext/GeantImporter.cc	80.95%	3 Missing and 5 partials :warning:
src/celeritas/io/detail/ImportDataConverter.cc	0.00%	8 Missing :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2100      +/-   ##
===========================================
+ Coverage    84.86%   84.88%   +0.01%     
===========================================
  Files         1255     1255              
  Lines        44186    44213      +27     
  Branches     16657    16517     -140     
===========================================
+ Hits         37499    37529      +30     
+ Misses        4901     4713     -188     
- Partials      1786     1971     +185     

Files with missing lines	Coverage Δ
src/celeritas/io/ImportOpticalMaterial.hh	95.12% <100.00%> (+0.38%)	:arrow_up:
src/celeritas/optical/gen/ScintillationData.hh	96.66% <100.00%> (+0.11%)	:arrow_up:
...rc/celeritas/optical/gen/ScintillationGenerator.hh	96.62% <100.00%> (+0.42%)	:arrow_up:
...leritas/optical/gen/detail/MatScintSpecInserter.hh	100.00% <100.00%> (ø)
src/celeritas/ext/GeantImporter.cc	93.12% <80.95%> (-0.30%)	:arrow_down:
src/celeritas/io/detail/ImportDataConverter.cc	24.60% <0.00%> (-0.81%)	:arrow_down:

... and 131 files with indirect coverage changes

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[sethrj]

@Rashika-Gupta could you merge upstream/develop and mark as "resolved" all the comments you've addressed? Thanks!