Remove the GetObjective() function from the solution.Solution Interface + Upgrade SymbolicMath.go version

[kwesiRutledge]

The GetObjective() function signature that we require for the solution.Solution interface is not necessary anymore given the existence of the new method: GetOptimalObjectiveValue. Removing the unnecessary getter.

Also, looks like the SymbolicMath.go version wasn't upgraded since v0.2.6. Whoops!

[Copilot]

Pull Request Overview

This PR removes the deprecated GetObjective() function from the solution.Solution interface and updates the SymbolicMath.go dependency to version v0.3.1. The GetObjective() method is no longer needed since GetOptimalObjectiveValue() now provides this functionality.

Key changes:

• Removed GetOptimalValue() method from the Solution interface and DummySolution implementation
• Removed the Objective field from DummySolution struct and all test instantiations
• Updated SymbolicMath.go dependency from v0.2.6 to v0.3.1

Reviewed Changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 1 comment.

File	Description
solution/solution.go	Removed GetOptimalValue() method signature from interface and added comprehensive documentation for GetValueMap()
solution/dummy_solution.go	Removed Objective field and GetOptimalValue() implementation from DummySolution
testing/solution/solution_test.go	Removed Objective field assignments from all test case DummySolution instantiations
go.mod	Updated SymbolicMath.go dependency from v0.2.6 to v0.3.1

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.37%. Comparing base (0214315) to head (e02ac4e).
⚠️ Report is 12 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #28      +/-   ##
==========================================
+ Coverage   86.76%   87.37%   +0.61%     
==========================================
  Files          27       35       +8     
  Lines        3687     4183     +496     
==========================================
+ Hits         3199     3655     +456     
- Misses        440      472      +32     
- Partials       48       56       +8     

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