chore(lib): calibrate path tracing

[jeertmans]

Calibrate path tracing utility such that it avoids invalid paths.

[codecov]

Codecov Report

Attention: Patch coverage is 79.48718% with 8 lines in your changes missing coverage. Please review.

Project coverage is 78.43%. Comparing base (1ff3d26) to head (b8c928c).
Report is 107 commits behind head on main.

Files with missing lines	Patch %	Lines
differt-core/src/geometry/triangle_mesh.rs	0.00%	7 Missing ⚠️
differt/src/differt/rt/utils.py	94.44%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #127      +/-   ##
==========================================
- Coverage   78.44%   78.43%   -0.02%     
==========================================
  Files          25       25              
  Lines        1670     1683      +13     
==========================================
+ Hits         1310     1320      +10     
- Misses        360      363       +3     

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[codspeed-hq]

CodSpeed Performance Report

Merging #127 will improve performances by 16.63%

_{Comparing calibration (b8c928c) with main (1ff3d26)}

Summary

⚡ 2 improvements
✅ 7 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	calibration	Change
⚡	test_compute_paths_in_simple_street_canyon_scene[20000-1]	2.1 s	1.8 s	+16.63%
⚡	test_compute_paths_in_simple_street_canyon_scene[None-1]	2.2 s	2 s	+15.14%