Publish a SCHISM Docker image to run rompy-schism workspaces

[rafa-guedes]

Adds a Docker image to run SCHISM on rompy-schism workspaces, published as ghcr.io/rom-py/schism. It follows the SWAN and XBeach images (ghcr.io/rom-py/swan, ghcr.io/rom-py/xbeach), so users can run a generated model without compiling SCHISM.

The image

docker/Dockerfile builds SCHISM v5.13.0 from its release tarball, verified against the checksum in docker/releases.txt. It uses Ubuntu 24.04, Open MPI and NetCDF, and the compiler settings in docker/schism. The image contains:

Command	What it does
schism	Hydrodynamics (scribed I/O, out2d_*.nc)
schism_wwm	Hydrodynamics coupled with WWM
combine_hotstart7	Merges the per-process hotstart files into one

The image is 390 MB. Running it looks like this:

DockerConfig(image="ghcr.io/rom-py/schism:5.13.0", executable="schism 2", mpiexec="mpirun", cpu=6)

It differs from the docker/schism build that the tests use in these ways:

• It has no ParMETIS -static flags. They fail against Ubuntu's shared MPI and NetCDF.
• WWM is built with a serial make. Its Fortran module dependencies are not ordered for -j.
• SCHISM reports its release. A tarball has no git history, so it is given the version through src/Core/schism_version_user.txt (schism -v prints v5.13.0). Before, it printed develop.
• It allows more MPI processes than cores (OMPI_MCA_rmaps_base_oversubscribe=1). Scribes mostly wait for output, so cpu=6 on a 4-core machine is normal; mpirun refuses it by default, and rompy's DockerConfig cannot pass --oversubscribe.
• It contains one release, and it is published.

docker/schism is unchanged.

Testing and publishing

• docker/test_image.py generates four workspaces from the test data and runs them in the image:
  • 2D tides;
  • 3D tides on the test vgrid.in;
  • tides with ERA5 and WWM driven by the WW3 test spectra;
  • a run writing hotstart files that combine_hotstart7 then merges.
• SCHISM exits with status 0 even when it aborts, so a run passes only when mirror.out reports a completed run, fatal.error is empty and out2d_1.nc is NetCDF.
• The hotstart case sets nhot = 1 directly in param.nml, because the Schout check of nhot fails on main. Write the vertical and vegetation parameters to &OPT, where SCHISM reads them #19 fixes that check.
• .github/workflows/docker.yml builds each release in docker/releases.txt, runs the test, and publishes to ghcr.io/rom-py/schism, with latest on the last release. Pull requests only build and test. It is the rompy-swan workflow with SCHISM names.
• Locally, all four cases pass with the image built from this branch.

After merging, the ghcr.io/rom-py/schism package has to be made public in the organisation's package settings.

WWM patch

The build applies docker/schism/patches/wwm-boundary-spectra-on-node.patch to the SCHISM source. WWM interpolates WAVEWATCH III boundary spectra to each wave boundary node from the two nearest spectra, weighted by 1/distance. A node exactly on a spectra point gets an infinite weight and no waves. That is common, because meshes often have boundary nodes on round coordinates, as do spectra from a regular grid. With the patch, such a node takes that point's spectrum. The same code is in SCHISM master, so this should also be reported upstream.