fix(routing): respect vehicle breaks edge-cases

[np96]

Description

Restore required breaks after route construction, initial-solution loading, and route changes. Skip time and distance breaks when the actual route finishes at or before their deadline, recheck skipped dimensions when another break extends the route, and remove unnecessary breaks when routes shrink.

Fixes both cases in #1195: the unreachable required break returns INFEASIBLE, and the late-break example returns cost 20 with no break stop. Configured break windows must still be compatible with the vehicle shift.

Validation: 129 local Python routing tests and 28 C++ tests passed. The two tests that grow and shrink routes with existing breaks also passed CUDA synchronization checking with zero errors. Regression coverage includes distance breaks, generated and injected routes, exact deadlines, waiting and return travel, dependent dimensions, mixed break types, and unchanged rejection of breaks outside the configured shift.

Checklist

• I am familiar with the Contributing Guidelines.
• Testing
  • New or existing tests cover these changes
  • Added tests
• Documentation
  • Documentation changes are excluded from this PR

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[coderabbitai]

📝 Walkthrough

Walkthrough

This PR adds logic in route cost computation to penalize missing required breaks when both BREAK and TIME dimensions are enabled, and adds a unit test that asserts a routing instance with an unreachable required break is infeasible.

Changes

Required Break Infeasibility Penalty

Layer / File(s)	Summary
Break Cost Penalty Logic cpp/src/routing/route/route.cuh	When both BREAK and TIME dimensions are active, compute_cost estimates depot arrival, counts required breaks whose break_latest ≤ arrival, reads route-present breaks (breaks_forward[*n_nodes]), and adds positive shortfall to infeasibility_cost[0][dim_t::BREAK].
Test Validation python/cuopt/cuopt/tests/routing/test_vehicle_properties.py	Adds test_required_break_unreachable_is_infeasible, which builds a 3-node scenario with a required break in an infeasible time window, solves, and asserts the solver returns infeasible status.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly identifies a routing fix for vehicle-break edge cases. It is concise and related to the changeset.
Description check	✅ Passed	The description directly explains the required-break handling, route changes, infeasibility behavior, and validation results covered by the changeset.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

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[rg20]

@np96

In the current form, I intentionally don't treat missing breaks as a violation as initial solutions are generated without breaks first and then breaks are inserted. Breaks should not be missed, I think there is some other bug in the code.

[github-actions]

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[np96]

Hi @rg20

Do you have a chance to check this draft? Looks like there was a lack of squeeze_breaks in certain places. this fixes both cases. Most of the PR are the tests.

[rg20]

Hi @rg20

Do you have a chance to check this draft? Looks like there was a lack of squeeze_breaks in certain places. this fixes both cases. Most of the PR are the tests.

Hi @np96,

I will have to spend sometime on rethinking the logic. Thanks for the PR.