Fix torch.stack and torch.cat recursion for CompositionScores

[yuanwuyuan9]

Description

torch.stack and torch.cat recurse indefinitely when their input sequence contains CompositionScores: the current dispatch unwraps only top-level arguments and passes nested wrappers back to PyTorch.

Recursively unwrap wrappers in lists, tuples, and dictionary values before calling the torch function. Preserve ordinary arguments and the existing tensor-return behavior. No new dependencies.

Add 16 regression cases covering stack/cat, list/tuple inputs, positional/keyword arguments, and mixed wrapper/tensor inputs. All 16 fail with RecursionError before the fix and pass afterward.

Fixes #1839

Type of change

• Bug fix (non-breaking change which fixes an issue)

Validation

Check	Result
New sequence-operation tests	16 passed
Existing CompositionScores protocol tests	8 passed
make unit-test	6784 passed, 61 skipped, 57 deselected, 6 xfailed, 306 warnings, 1 rerun
Gated-hooks benchmark test file, reruns disabled	4 passed
mypy	No issues in 386 source files
Formatting and git diff --check	Passed

The unit suite ran on CPU with OMP_NUM_THREADS=1 MKL_NUM_THREADS=1; uv synchronization was disabled to preserve the installed environment and lockfile. One test in test_benchmark_gated_hooks_fire.py required a rerun. All four tests in that file subsequently passed with --reruns 0; the initial failure cause remains undetermined. Full make test-pr and CI have not been verified locally.

Checklist

• I have commented my code, particularly in hard-to-understand areas — updated the dispatch docstring to describe container unwrapping.
• I have made corresponding changes to the documentation — no separate documentation update needed for this bug fix.
• My changes generate no new warnings — targeted runs show the same SWIG warnings; a full-suite warning comparison was not performed.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes, with the configuration and rerun noted above.
• I have not rewritten tests relating to key interfaces which would affect backward compatibility.

[jlarson4]

Hey @yuanwuyuan9, thanks for the contribution! Just one note about test location

[jlarson4]

Looks good! Thanks for the contribution @yuanwuyuan9