fix: improve error visibility across publish pipeline

[brendanjryan]

Problem

When commands fail in CI, error output is swallowed — you get Process completed with exit code 1 with zero context. Additionally, subprocess errors (cargo, python, twine, git) give generic io error messages when binaries aren't found, and omit stdout/exit codes on failure.

Changes

action.yml

• Fix changelogs version output swallowing — same set -e bug as publish: use && exit=0 || exit=$? so output is always echoed before failing
• Fix changelogs publish output swallowing — capture exit code separately so echo "$output" always runs

python.rs

• python -m build — wrap .output() with .map_err() for clear "command not found" errors; include stdout, stderr, and exit code on failure
• twine upload — same treatment

rust.rs

• cargo publish — same treatment: .map_err() on .output(), include stdout + stderr + exit code

publish.rs

• git tag — log failures instead of silently ignoring them when git tag -a exits non-zero

[vercel]

@brendanjryan is attempting to deploy a commit to the Wevm Team on Vercel.

A member of the Team first needs to authorize it.