fix(SU2_PY): Fix Custom Objective Function for Unsteady Adjoint

[shbhmexe]

Description

Defining Custom Objective Function does not work with shape_optimization.py. The historyMap.py is updated in order to fix the problem.

This PR is a rebased and fixed version of #2587 (original author: @ErcanUmut60), which was approved but stalled due to merge permissions.

Additional Fix: The updateHistoryMap.py script has been updated to handle cases where HistoryFieldType is passed as a variable (without :: separator), preventing script crashes on some existing files in develop.

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Proposed Changes

Files Modified:

1. SU2_CFD/src/output/CFlowOutput.cpp

   • Added custom objective function output field for unsteady adjoint cases

2. SU2_PY/updateHistoryMap.py

   • Fixed parsing logic to handle field types with and without :: separator
   • Ensures compatibility with existing code in develop branch

3. SU2_PY/SU2/io/historyMap.py

   • Regenerated using the updated script

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Checklist

• I am submitting my contribution to the develop branch.
• My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
• My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
• I used the pre-commit hook to prevent dirty commits and used pre-commit run --all to format old commits.
• I have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

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Related Issues/PRs

• Closes Fixing Custom Objective Function for Unsteady Adjoint  #2587 (original PR by @ErcanUmut60)
• Related to fix(SU2_CFD,SU2_PY,Common): Fix typos, code style, and safety guards #2660 (Python script improvements)

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Testing

• Locally verified that updateHistoryMap.py runs successfully
• Generated historyMap.py matches expected output
• No compilation errors expected