Restore 3.15t CI pipeline

[leofang]

xref: #2108 (comment)

[leofang]

Blocked by #2171.

[rwgk]

To mention this here directly: #2171 turns out to be a general Python vs NumPy compatibility issue. A full report is here:

• Python 3.15t segfault when importing numpy.random #2171 (comment)

[lijinf2]

Got some bandwidth. I will take a look at this issue since it is still open and assigned. But let me know if I am missing anything here. Mostly background study at this stage.

[lijinf2]

It looks like the bug (in the Pathfinder dependency) has been fixed by upgrading ubuntu from 22.04 to 24.04 in CI (According to Issue #2171 and PR #2211). Should be safe to close this issue @leofang?

[leofang]

Yes, thanks Jinfeng. Sebastian fixed it in #2211. Closing.