Feature fortitude lint

[lamkina]

This pull request introduces automated linting for Fortran code using Fortitude in the GitHub Actions workflow. It adds a reusable workflow configuration and a project-specific Fortitude configuration file to enforce code quality and style standards.

GitHub Actions workflow integration:

• Added .github/workflows/fortitude.yaml to define a reusable workflow that runs Fortitude checks on Fortran code. The workflow supports configurable timeout and fail behavior, sets up Python, installs Fortitude, downloads a global config if a local one is missing, and runs the lint check with the appropriate exit code.

Fortitude configuration:

• Added fortitude.toml to specify linting rules: sets line length to 120, selects core checks, ignores specific style rules, and excludes files matching certain patterns.

Expected time until merged

1-3 days

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

See this PR for testing logs.

Checklist

• I have run ruff check and ruff format to make sure the Python code adheres to PEP-8 and is consistently formatted
• I have formatted the Fortran code with fprettify or C/C++ code with clang-format as applicable
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation

[sseraj]

One major problem is that Fortitude does not recognize PETSc syntax

src/adjoint/adjointUtils.F90:51:9: E001 Syntax error
   |
50 |           ! PETSc Matrix Variable
51 | /         Mat :: matrix
52 | |
53 | |         ! Input Variables
   | |__________________________^ E001

I am also seeing some false positives with E001 where the entire file is flagged.
This happens with src/adjoint/adjointExtra.F90 in ADflow, for example.

[sseraj]

This should be an on/off flag instead?

[sseraj]

I think we should enable C121 so we have explicit use statements

[sseraj]

Maybe ignore S102 as well?
S102 [*] need at least 2 spaces before inline comment
This is something that should be handled automatically by a formatter. fprettify added a rule for this recently, but it hasn't made it into a release yet.

On a related note, I think we will need to keep fprettify because Fortitude does not have the same formatting capabilities.