Ensure VTKHDF outputs are closed on simulation failures

[AhmedSalih3d]

Motivation

• Simulations that error (not via Ctrl+C) could leave VTKHDF files open because finalization was only triggered for exit/interrupt paths, so add a robust single-use finalizer to always close output on failure.

Description

• Add a FinalizeOnce! helper in RunWithSimulationFinalizer! to ensure output finalization runs exactly once across normal exit, Ctrl+C, Julia exit, and ordinary exceptions (src/SPHCellList.jl).
• Replace direct finalization calls in the atexit handler and interrupt path with FinalizeOnce! and add handling for non-interrupt exceptions that finalizes with log_status="failed" before rethrowing.
• Add a regression test that invokes RunWithSimulationFinalizer! with a synthetic error and asserts close_files was called (test/runtests.jl).

Testing

• Ran julia --project=. -e 'using SPHExample' which precompiled and loaded the package successfully.
• Executed an inline test that calls RunWithSimulationFinalizer! with a forced error("boom") and verified the provided close_files was invoked (test passed).
• Ran the full test suite with julia --project=. -e 'using Pkg; Pkg.test()' which exercised the new regression test but the overall test run failed due to a pre-existing unrelated failure in the time stepping test (Δt method signature mismatch).

---

Codex Task