Reject unsupported periodic adjoint, radiation and structural solvers

[rois1995]

Proposed Changes

Unsupported periodic solver combinations are accepted without a periodic boundary implementation. This PR rejects them before solver construction.

Develop accepts periodic continuous-adjoint, radiation and structural configurations without implementations of those periodic boundaries. Configuration validation now stops these combinations with a specific error before solver construction.

Complete BOX configuration controls verify that develop accepts each input and the fixed source rejects it for the intended reason. A supported direct-flow control remains accepted. This adds support diagnostics; it does not implement those missing solvers.

Validation of the combined periodic source passes serial, partitioned MPI2, OpenMP2 and MPI2×OpenMP2 (10 cases / 3175 serial assertions). Individual branch CI and complete regression/reference checks are pending. Test configurations, meshes, logs and before/after values are in the testcase comment.

The PR only adds configuration guards. The additional unit tests and subprocess runner were removed following review; the before/after configurations and diagnostic logs remain available in the testcase comment.

Related Work

• MPI Point-to-Point Refactoring + New Periodic BC Implementation #652 introduced the current periodic implementation.
• Fixes for rotational periodic boundaries: implicit solver, multigrid and limiters #2961 lists the eight related periodic-boundary PRs. Their numbering groups the topics; it does not imply a linear dependency chain.

PR Checklist

• I am submitting my contribution to the develop branch.
• My contribution generates no new compiler warnings (complete branch CI pending).
• My contribution is commented and consistent with SU2 style.
• I ran the repository pre-commit checks on the changed files.
• I verified the contribution with the published before/after configuration controls (unit-test additions removed following review).
• I have updated appropriate documentation, if necessary.

[rois1995]

Test cases

Reproducers, configurations, numeric logs and scripts: support. Develop = 6db10127d1; BOX fixtures generate their meshes. The original B–D evidence above was recorded before the expanded follow-ups.

Configuration	develop	fixed
Continuous adjoint + periodic	accepted (exit 0)	intended early support error
Radiation + periodic	accepted (exit 0)	intended early support error
Elasticity + periodic	accepted (exit 0)	intended early support error
Supported direct flow + periodic	accepted	accepted

The full configs, exact diagnostic logs and Python check are provided. The combined diagnostic runner also verifies the four streamwise restrictions handled in part D. Missing continuous-adjoint/radiation/structural periodic physics is not implemented by these guards.

Combined release checks: serial and OpenMP2 pass 10 cases / 3175 assertions; partitioned MPI2 and MPI2×OpenMP2 pass on both ranks (2334 / 2238 assertions). These are combined-source checks, not standalone builds of every branch. Complete branch CI and full regression/reference checks remain pending.

[joshkellyjak]

Nice catch, not sure a unit test for this functionality is strictly necessary

[joshkellyjak]

"MARKER_PERIODIC is not currently supported in the continuous adjoint solver. Use MATH_PROBLM= DISCRETE_ADJOINT"

same for two below

[rois1995]

Updated all three messages in 522998a to use "not currently supported". The discrete-adjoint suggestion remains only in the continuous-adjoint error.

[rois1995]

@joshkellyjak Removed the additional unit tests and subprocess runner in 522998a, as suggested. The PR now only adds the configuration guards; the before/after configurations and diagnostic logs remain linked in the testcase comment.