Gate configured Sphere PTO cases in Python CI

[cmccomb]

What changed

• Bundle the exact pinned Sphere HDF5 and all 400 s MATLAB output samples for the configured passive PTO and pretension variant, with source hashes and job provenance.
• Run the existing public WEC body-local attachment, heave, PTO stroke/speed/force/power, and controller gates in ordinary Python CI. The MATLAB source workflow still uses the original CSVs and unchanged limits.
• Record the regression gate in the parity ledger. These are already-paired derived configurations, so the Sphere case badge does not change.

Verification

• Portable focused tests: 2 passed in 6.89 s.
• Live-source focused tests: 2 passed in 6.74 s.
• Every archived array was checked for exact equality with its source CSV.
• Full local suite: 272 passed, 329 skipped in 375.67 s; combined line-and-branch coverage 78.796% (79% display).
• Coverage and parity badge checks, and git diff --check, passed.