Avoid setup-uv cache races

[fazpu]

Summary

• give each CI matrix entry a distinct setup-uv cache suffix
• keeps the Node 24 action update clean of cache-reservation annotations

Validation

• git diff --check
• uv run python -c "import yaml, pathlib; [yaml.safe_load(p.read_text()) for p in pathlib.Path('.github/workflows').glob('*.yml')]; print('workflow yaml ok')"