ci: pin pyarrow <25 to unblock CI (#841)

* ci: pin torch <2.13 to unblock CI

torch 2.13.0 (released after 2026-07-02) causes the 'Run processing tests
sequentially' step to hang in test_optimize_race_condition — macOS jobs hit
the 1h timeout, Linux jobs get killed. The last green main run (2026-07-02)
used torch 2.12.1; every run since resolves the unpinned torch to 2.13 and
fails. Pin as a stopgap while the hang is root-caused.

* ci: pin pyarrow <25 to unblock CI (parquet segfault regression)

Author: bhimrazy

requirements/extras.txt

@@ -1,6 +1,6 @@
 pillow
 viztracer
-pyarrow
+pyarrow <25.0.0  # TODO: unpin once pyarrow 25 parquet segfault is resolved
 tqdm
 lightning-sdk==2026.2.6 # Must be pinned to ensure compatibility
 google-cloud-storage

requirements/test.txt

@@ -10,7 +10,7 @@ pytest-rerunfailures ==16.1
 pytest-random-order ==1.2.0
 pytest-xdist >=3.8.0
 pandas
-pyarrow >=20.0.0
+pyarrow >=20.0.0,<25.0.0  # TODO: unpin once pyarrow 25 parquet segfault is resolved
 polars >1.0.0
 lightning
 transformers >=4.51.0