Add tag-triggered release zip workflow

[tonythethompson]

Closes #50

Adds a GitHub Actions workflow that uploads bash-env-nushell-{version}.zip when a semver tag is pushed (tags here use 0.19.0 style, no v prefix).

Archive layout (matches what hash-pinned package managers expect):

bash-env-nushell-0.19.0/
├── bash-env.nu
└── …

Built with git archive so the zip is byte-stable for a given tag.

Triggers:

• push on semver tags (future releases)
• workflow_dispatch with a tag input (e.g. 0.19.0) to backfill an asset on an existing tag

Modeled after vyadh/nutest release.yaml; happy to adjust naming or trigger rules.

After this lands, the Numan registry can switch from our hosted mirror to your release asset on the next tag (or after a one-off dispatch for 0.19.0 if you want).

[tesujimath]

Thanks for this!

Can I trigger the workflow for e.g. 0.19.0 before merging, or does that require it to be on main? If the former, would appreciate a pointer!

[tonythethompson]

Good question — merge first, then backfill.

\workflow_dispatch\ only runs workflows that exist on the branch you pick in the Actions UI. Until this PR is on \main, the Release workflow won't show up there.

After merge:

1. Actions → Release → Run workflow
2. Branch: \main\
3. Tag input: \

[tesujimath]

I ran that on 0.19.0. You happy with the result?

[tonythethompson]

Yes, looks perfect. Verified \�ash-env-nushell-0.19.0.zip\ on the 0.19.0 release: correct layout (\�ash-env-nushell-0.19.0/bash-env.nu), byte-stable sha256 \8d5c18b9…. Switching the Numan registry to your upstream URL and dropping our mirror. Thanks for running the backfill.