Improve cmdrun and testing

[p-ortega]

This pull request introduces several improvements to the project's continuous integration workflows, test infrastructure, and codebase organization. The main changes include enabling scheduled CI runs, broadening workflow triggers, adding CLI-based testing, and refactoring the CLI entrypoint for better compatibility.

Continuous Integration Improvements:

• Enabled scheduled CI runs at 8 AM UTC daily by uncommenting and activating the schedule trigger in both .github/workflows/tests_main.yml and .github/workflows/tests_macos.yml. [1] [2]
• Broadened the pull request workflow triggers to match all feature/** branches instead of just feature/externalio. [1] [2]

Testing Enhancements:

• Updated autotest/test_benchmark.py to support running tests via the CLI by adding a test_cli flag to run_test and invoking the mf6rtm CLI using subprocess when set. The test05 benchmark now uses this new CLI-based test path. [1] [2]

Codebase Cleanup and Refactoring:

• Removed the __author__ and __version__ metadata from mf6rtm/__init__.py for a cleaner module interface.
• Removed the obsolete CLI entrypoint code from mf6rtm/__main__.py to centralize CLI logic.
• Refactored the run_cmd function in mf6rtm/simulation/solver.py to accept an optional cwd argument for improved console script compatibility and added a docstring.
• Minor typing improvement: imported Optional in mf6rtm/simulation/solver.py.

[p-ortega]

Need to wait for the new nightly build

[p-ortega]

We are finally winning this

[aufdenkampe]

@p-ortega, I'm glad this is finally working better! Thanks for pushing this so hard in recent weeks!!!

[p-ortega]

@aufdenkampe No worries at all. Also, mf6rtm is working with the latest versions of mf6 that are in the nightly build