feat: Unweighted shortest path

[joweich]

Value add:

• capabilities to calculate the shortest path between one start and one end vertex
• calculation for unweighted graphs; weighted graphs will be addressed in a follow-up PR

[github-actions]

Hi there! Thank you for creating your first pull-request on the Graaf library :)

[codecov]

Codecov Report

Patch coverage: 99.06% and project coverage change: -0.20 ⚠️

Comparison is base (23b898b) 100.00% compared to head (aaec2e0) 99.80%.

Additional details and impacted files

@@             Coverage Diff             @@
##              main      #18      +/-   ##
===========================================
- Coverage   100.00%   99.80%   -0.20%     
===========================================
  Files            9       12       +3     
  Lines          411      518     +107     
===========================================
+ Hits           411      517     +106     
- Misses           0        1       +1     

Impacted Files	Coverage Δ
src/graaflib/algorithm/shortest_path.tpp	96.87% <96.87%> (ø)
src/graaflib/algorithm/shortest_path.h	100.00% <100.00%> (ø)
test/graaflib/algorithm/shortest_path_test.cpp	100.00% <100.00%> (ø)

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[bobluppes]

Thanks for working on this, looks very good already! Added some early feedback.

I would also be happy to merge the BFS implementation and to add support for weighted graph search in a follow-up PR.

[joweich]

@bobluppes any idea why codecov does not catch the closing curly bracket here? Building and testing runs flawlessly

[bobluppes]

@bobluppes any idea why codecov does not catch the closing curly bracket here? Building and testing runs flawlessly

This seems to be a weird quirck of lcov, I will see if we can configure the tool differently.

Currently the codecov CI does not block from merging so for this PR we can leave it as-is. In a follow-up I will configure the CI such that we don't need 100% coverage for it to pass, as I think 95% should also be fine.

[bobluppes]

Looks very good, thanks for implementing this 🚀