fix(ci): fix cargo-shear installation in workflows

[dev-nicelee]

Summary

This PR fixes the CI workflow setup so the unused dependency check installs cargo-shear before running cargo shear.

What's added

• Adds the explicit tool: cargo-shear input to taiki-e/install-action in the CI workflow
• Applies the same fix to the release workflow check job
• Keeps the existing pinned install action version unchanged

Motivation

The CI check was failing because cargo shear ran without the cargo-shear cargo subcommand installed. The install action was present, but no tool was specified, so it emitted a warning and skipped installing cargo-shear.

Testing

Verified the workflow files parse as YAML:

ruby -e 'require "yaml"; ARGV.each { |f| YAML.load_file(f); puts "ok #{f}" }' .github/workflows/ci.yml .github/workflows/release.yml
# Output:
# ok .github/workflows/ci.yml
# ok .github/workflows/release.yml

Also verified the diff has no whitespace errors:

git diff --check

[vlwkaos]

Thanks for the fix. The actual cargo-shear workflow change looks right to me, but this PR branch still includes commits that I force-pushed out of main. Sorry for the force push and the stale base trouble.

Could you please rebase this branch onto the current main, or cherry-pick only your workflow commit onto a fresh branch based on the new main?

The commit to keep is:

• 33b9c7c Fix cargo-shear installation in workflows

The commits that should disappear from this PR after rebasing are:

• 7c0ae76 feat(retrieval): add linked code unit retrieval
• 6c094e8 test(retrieval): add linked synthesis evidence fixture
• 5fc3ba6 docs(retrieval): document linked retrieval workflow

I reviewed the intended isolated change in 33b9c7c:

• It only changes .github/workflows/ci.yml and .github/workflows/release.yml.
• taiki-e/install-action expects with.tool, and cargo-shear is a supported tool, so this is the correct shape.
• Local verification on current main: cargo build --no-default-features --features llama-openmp passed.
• Local verification on current main: cargo test --no-default-features --features llama-openmp passed.
• I could not run cargo shear locally because the subcommand is not installed in my local environment; the workflow install step is the thing this PR fixes.

Once the branch is rebased/cherry-picked so the PR contains only the two workflow files, this should be good to merge from my side.

[dev-nicelee]

@vlwkaos I fixed the conflicts and it seems like mergeable.
Thanks for the comment!🙇🏻

[vlwkaos]

Thanks for the contribution!