[CanReader]

• download release archives outside the checkout so cargo publish sees a clean tree

What this changes

The publish job now downloads the build archives to $RUNNER_TEMP/dist instead of dist/ in the repo.

Why

The v0.3.1 release got through the tag check and the builds, then cargo publish stopped with "7 files in the working directory contain changes that were not yet committed", which were the downloaded archives in dist/. Nothing was uploaded to crates.io.

How it was verified

• cargo test passes
• cargo clippy --all-targets -- -D warnings is clean
• Ran cuda_parity on a GPU
• Trained an example in --release
• No GPU here, CUDA side not runtime tested

Workflow change only. The YAML parses, and this PR runs the release workflow without the publish steps, so the real publish is only proven by the next tag.

Checklist

• Every new or changed backward rule has a gradcheck case
• Every new kernel has a cuda_parity case
• tensor/ops and autograd/ops still mirror each other
• Public items have /// docs