fix(deps): align pyproject DeepEP pin with the container build (#3608)

DeepEP is pinned in two places that nothing keeps in sync:

  docker/Dockerfile   ARG DEEPEP_COMMIT = 42144303 (DeepEP #638, 2026-05-20)
  pyproject.toml      deep_ep.rev       = 7febc6e2 (DeepEP #580, 2026-02-09)

The Dockerfile pin was bumped to pick up DeepEP #638 (pads
max_num_of_tokens_per_rank to the combine-kernel chunk size, fixing the
HybridEP JIT static_assert), but the uv source was left behind. Since the
`moe` extra is not part of `all`, the container installs DeepEP only from
the Dockerfile source build -- so CI never exercised the stale pin, while
anyone running `uv sync --extra moe` or `pip install nemo_automodel[moe]`
outside the container got a DeepEP three months older than the one every
recipe was validated against.

Bump the uv source to 42144303 and update the declared
`[[tool.uv.dependency-metadata]]` version to `v1.2.1+4214430` to match
(deep_ep builds as `1.2.1+$(git rev-parse --short HEAD)`; uv trusts this
string instead of building during resolution). Both lock files are
refreshed accordingly.

Add tests/unit_tests/test_deepep_pin_consistency.py so the next bump
cannot land half-applied: it fails when the two pins disagree, and when
the declared version stops naming the pinned commit.

Signed-off-by: Alexandros Koumparoulis <akoumparouli@nvidia.com>