Remove unused cuda-oxide workspace dependencies

[nihalpasham]

Summary

Remove four unused declarations from cuda-oxide's workspace dependency table. The newer Cargo introduced by #1482 reports these entries whenever a workspace command runs.

Changes

Remove cuda-bindings, futures, fuzzer, and mir-importer from [workspace.dependencies]. No member inherits these declarations. Workspace members and dependencies declared directly by consumers stay intact; neither lockfile changes.

Testing

• Full cargo metadata --locked --offline --format-version 1 output is identical before and after the change on both main and exp/cuteir-translation.
• cargo oxide run gemm_views passed on the experimental checkout with this same four-line cleanup: GPU results matched the CPU reference, and safe/raw pairs were bitwise identical. Its log contains no warnings after also uninstalling the obsolete global cargo-oxide executable on that machine.
• git diff --check passed. Full compiler tests were not rerun for removal of uninherited manifest entries.

Checklist

• Commit signed and signed off.
• No new source files or examples; SPDX additions are not applicable.