[build] chore: bump transformer-engine to release_v2.16.post

[ko3n1g]

Background

Bumps TransformerEngine from the release_v2.16_post head (d64bc14, landed in #4527) to the newer release_v2.16.post head (b9d690e). Upstream re-cut the post branch under the dotted name; this re-points main at it. Companion bumps: Megatron-Bridge r0.5.0 (#4535), Megatron-LM main + core_r0.18.0.

What changed

• override-dependencies TE pin d64bc14d → b9d690e0 (release_v2.16.post head).
• Regenerated uv.lock (TE entry only).

Details

• pyproject.toml:132 — transformer-engine @ git+...@b9d690e042b1c4e455214e7dab65d6d3512c05d6.
• uv.lock — transformer-engine 2.16.0+d64bc14d → 2.16.0+b9d690e0; TE's transitive dependencies unchanged. Lockfile stays revision = 2.
• Relocked in-container (uv lock).

Tested

• uv lock clean: Resolved 345 packages, Updated transformer-engine v2.16.0+d64bc14d -> v2.16.0+b9d690e0.
• needs-more-tests + full-test-suite applied (TE is high-blast-radius).

[claude]

LGTM — clean TE pin bump (d64bc14d → b9d690e0, both release_v2.16.post). Version stays 2.16.0, lockfile update is consistent, no transitive dependency changes. Labels needs-more-tests + full-test-suite are correctly applied for blast radius.

Suggested test cases

No perf tests impacted — no recipe or performance configs were changed in this PR. CI coverage via the needs-more-tests and full-test-suite labels (L0+L1+L2) is the appropriate validation for a TE bump.