Fix #426: SubsetSum -> CapacityAssignment reduction

[zazabap]

Summary

Implements the SubsetSum -> CapacityAssignment reduction rule from Garey & Johnson SR7 (Van Sickle and Chandy, 1977).

Each element becomes a communication link with 2 capacities. The delay budget constraint forces the assignment to mirror a valid subset-sum solution, and the minimum cost equals B iff a subset summing to B exists.

Fixes #426

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.85%. Comparing base (f29cfb1) to head (9c2e072).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #799   +/-   ##
=======================================
  Coverage   97.85%   97.85%           
=======================================
  Files         625      625           
  Lines       68311    68311           
=======================================
  Hits        66846    66846           
  Misses       1465     1465           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.