feat(moeo): add finalize() lifecycle hook for algorithm post-processing

[evvaletov]

Summary

Adds a finalize() extension point to the multi-objective algorithm
hierarchy, allowing algorithms to perform post-processing after external
population modifications.

• moeoAlgo: virtual destructor + hasFinalize() const (default false)
• moeoPopAlgo<MOEOT>: virtual finalize(eoPop<MOEOT>&) (default no-op)
• moeoNSGAII: implements finalize() to recompute dominance-depth
  fitness and crowding diversity assignments

Motivation

In island model configurations, immigrant individuals are integrated into
an island's population between generations. NSGA-II's fitness and diversity
values become stale after integration — the non-dominated sorting ranks and
crowding distances no longer reflect the actual population composition.
Without recomputation, selection pressure degrades until the next natural
generation boundary.

The finalize()/hasFinalize() pattern lets the island model trigger
recomputation only on algorithms that need it, without coupling the island
infrastructure to specific algorithm internals.

Changes

File	Change
moeo/src/algo/moeoAlgo.h	Added virtual destructor, hasFinalize() const
moeo/src/algo/moeoPopAlgo.h	Added virtual void finalize(eoPop<MOEOT>&) {}
moeo/src/algo/moeoNSGAII.h	Override: recomputes fitnessAssignment + diversityAssignment

[nojhan]

Good idea, thanks!

I would be willing to merge this if I can review the code (same comment than for PR #83 )

[evvaletov]

Rebased onto HEAD, should be reviewable now.

On the design: finalize() exists for the island model (PR #86). After immigrants are integrated into a population, NSGA-II's dominance depth and crowding distance become stale. finalize() lets the island call fitnessAssignment + diversityAssignment on the updated population. The hasFinalize() query on the non-template base avoids coupling the island model to specific algorithm types.

[nojhan]

This is a good idea. I'm just wondering why adding a const check for the feature instead of derivating a new interface?

My immediate thought would have been to add some kind of moeoAlgoFinalized abstract class adding the finalize interface. That way, one don't rely on a test with hasFinalize and the compiler double-checks the interface for you, which should lead to less bugs.

But maybe there is some problem with that?