Add figure of merit enum

[chris-ashe]

This pull request refactors how figures of merit (FoM) are represented and used throughout the PROCESS codebase. The main improvement is the introduction of a new FiguresOfMerit enumeration in numerics.py, replacing the previous use of the lablmm list and scattered constants. This makes the code more maintainable, type-safe, and easier to extend. All references to figures of merit in both code and documentation have been updated to use this new enum, and related descriptions and logic have been centralized.

Core Refactoring:

• Introduced the FiguresOfMerit enum in process/data_structure/numerics.py to represent all available figures of merit, each with an associated integer value and description.
• Removed the legacy lablmm list and the OBJECTIVE_NAMES dictionary, updating all code to use the new enum for descriptions and names.

Code Updates:

• Refactored all code references to figures of merit to use FiguresOfMerit, including in init.py, scan.py, and plotting modules, ensuring consistent and clear usage.
• Updated the objective function for case 5 to use big_q_plasma directly, aligning with the new enum's semantics.

Documentation Updates:

• Updated documentation to reference FiguresOfMerit instead of lablmm, and clarified instructions for adding new figures of merit.

These changes modernize and centralize how figures of merit are handled, making future extensions and maintenance significantly easier.## Description

Checklist

I confirm that I have completed the following checks:

• My changes follow the PROCESS style guide
• I have justified any large differences in the regression tests caused by this pull request in the comments.
• I have added new tests where appropriate for the changes I have made.
• If I have had to change any existing unit or integration tests, I have justified this change in the pull request comments.
• If I have made documentation changes, I have checked they render correctly.
• I have added documentation for my change, if appropriate.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 44.59459% with 41 lines in your changes missing coverage. Please review.
✅ Project coverage is 50.17%. Comparing base (46626d2) to head (5547521).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
process/core/solver/objectives.py	2.56%	38 Missing ⚠️
process/core/io/plot/summary.py	33.33%	2 Missing ⚠️
process/core/scan.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4272      +/-   ##
==========================================
+ Coverage   50.13%   50.17%   +0.04%     
==========================================
  Files         151      151              
  Lines       29349    29378      +29     
==========================================
+ Hits        14714    14741      +27     
- Misses      14635    14637       +2     

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[Copilot]

Pull request overview

This PR refactors PROCESS’s “figure of merit” (FoM) handling by introducing a centralized FiguresOfMerit IntEnum in process/data_structure/numerics.py, replacing the legacy lablmm list and the OBJECTIVE_NAMES mapping, and updating call sites in the solver, scan/output, plotting, and documentation.

Changes:

• Adds FiguresOfMerit enum (ID + description) and removes lablmm initialization/usage.
• Refactors objective evaluation and various outputs/plots to derive FoM labels from the enum.
• Updates documentation to refer to FiguresOfMerit rather than lablmm.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
process/data_structure/numerics.py	Introduces FiguresOfMerit enum and removes legacy lablmm list.
process/core/solver/objectives.py	Replaces OBJECTIVE_NAMES and switches FoM selection logic to enum-based dispatch.
process/core/scan.py	Uses enum descriptions for objective function naming in post-optimise output.
process/core/io/plot/summary.py	Replaces objective-name mapping with enum usage in plot headers/cover page text.
process/core/io/plot/solutions.py	Uses enum descriptions when falling back to minmax for older MFiles.
process/core/init.py	Uses enum descriptions when printing the run summary header.
documentation/source/io/input-guide.md	Updates minmax help text to reference FiguresOfMerit.
documentation/source/development/add-vars.md	Updates “add FoM” instructions to point to numerics.py + enum.

Comments suppressed due to low confidence (1)

process/core/solver/objectives.py:55

• objective_function compares against enum members that don't exist in FiguresOfMerit (e.g. TF_PF_COIL_POWER, FUSION_GAIN, INJECTED_POWER, PLANT_AVAILABILITY, etc.). This will raise AttributeError at runtime. Update these comparisons to use the actual enum member names defined in process/data_structure/numerics.py (or rename the enum members to match the names used here) so the mapping for cases 4/5/11/15/16/18/19 is consistent.

    if figure_of_merit == FiguresOfMerit.MAJOR_RADIUS:
        objective_metric = 0.2 * physics_variables.rmajor
    elif figure_of_merit == FiguresOfMerit.NEUTRON_WALL_LOAD:
        objective_metric = physics_variables.pflux_fw_neutron_mw
    elif figure_of_merit == FiguresOfMerit.TF_PF_COIL_POWER:
        objective_metric = (tfcoil_variables.tfcmw + 1e-3 * data.pf_power.srcktpm) / 10.0
    elif figure_of_merit == FiguresOfMerit.FUSION_GAIN:
        objective_metric = data.current_drive.big_q_plasma
    elif figure_of_merit == FiguresOfMerit.COST_OF_ELECTRICITY:

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.