Expand and regroup SAI GPU validation

[Stardust0831]

Reminder

• I have read AGENTS.md and docs/developers_guide/agent_governance.md.
• I have linked an issue or explained why this PR does not need one.
• I have added adequate control tests and case coverage.
• I have listed exact verification evidence and results.
• I have described user-visible behavior changes, including INPUT parameter changes.
• I have explained core-module impact.
• I have requested any needed governance exception below.

Linked Issue

Follow-up to #7665. The WT CUDA numerical correction required by the added OFDFT case was merged in #7763. This PR does not close a separate issue.

Verification

• The control test suite passes 45/45 and the agent governance check reports no findings.
• Exact-head SAI GPU validation passed all 123 cases with 0 failures and 0 infrastructure errors: https://github.com/Stardust0831/abacus-develop/actions/runs/30750811126
• The uploaded run metadata identifies candidate af7d372702878e13ba59b7688b6cb995254ed216.
• Compile and every folder component passed, including tests/07_OFDFT for the Fix WT KEDF CUDA reciprocal-space indexing #7763 regression case and the 2-node cuSolverMp smoke.

What changed?

• Add 73 existing tests/01_PW cases to the SAI single-GPU Slurm array and force their copied INPUT files to use the GPU without modifying repository fixtures.
• Add tests/07_OFDFT/31_OF_KE_WT_GPU to the matrix.
• Use 2 GPUs for ordinary multi-rank cases, retain three representative 4-GPU cases, and run the cuSolverMp smoke on 2 nodes with 4 GPUs per node.
• Report GitHub component checks and summaries by the test folder while keeping resource-homogeneous Slurm arrays underneath.
• Broaden retry recognition for the observed PMIx pilot-startup failure signature.

The matrix grows from 49 to 123 cases. The measured case allocation in the exact-head run was 1768 GPU-seconds.

Governance Notes

• INPUT/docs changes: no ABACUS INPUT behavior changes; GPU selection is applied only to isolated test copies.
• Core module impact: none; no source/ files are changed.
• Exceptions requested: none.