[tensornull]

Scheduled CI repeatedly fails at twine check because the isolated Hatchling build now emits Core Metadata 2.5 while the locked Twine validator supports formats through 2.4. Explicitly select Metadata 2.4 for both the wheel and sdist targets, and exercise both the sdist-to-wheel and direct-wheel build paths against the locked validator.

Validation:

• Reproduced the reported Metadata 2.5 failure before the fix; both new build regressions pass after it, including on Python 3.10.
• 777 offline tests pass on Python 3.14, together with lint, formatting, typing, version/document checks, secret scanning, workflow semantics, and actionlint.
• Both distributions pass Twine and artifact inspection, independent clean installation and README example smoke tests, and the copied standalone repository gate.

Remote validation: CI run 39243125049 completed successfully on commit a483fe3c09fee7fb0a8b83d711287c96716c6555, with all nine jobs passing.