bundle: add cleanup support to npm, cargo, go, and uv extensions

[mvanhorn]

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• AI was used to generate or assist with generating this PR. Claude (Anthropic) was used to help write the cleanup methods and tests. All code was reviewed for correctness, tested locally with brew lgtm --online, and verified by running brew bundle cleanup against a real Brewfile on my machine.

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brew bundle cleanup handles formulae, casks, taps, VSCode extensions, and Flatpak packages not listed in the Brewfile. But it silently ignores npm, cargo, go, and uv packages.

The Extension base class already defines cleanup_heading, cleanup_items, and cleanup! hooks. Flatpak and VSCode Extension override them. The other 4 extensions don't, so their packages are invisible to cleanup.

This PR adds the same 3 overrides to npm, cargo, go, and uv, following the flatpak pattern:

Extension	cleanup! command
npm	npm uninstall -g NAME
cargo	cargo uninstall NAME (with CARGO_HOME/RUSTUP_HOME env)
go	Removes binary from GOBIN/GOPATH after matching via go version -m
uv	uv tool uninstall NAME

Tested locally. With 6 go packages installed and a Brewfile listing only one, cleanup now reports the other 5:

[MikeMcQuaid]

Hey @mvanhorn! Thanks, looking good so far.

Main concern here is that folks are may be surprised when they brew bundle cleanup --force and it nukes all their global cargo/go/npm/uv files.

I'm not sure how best to handle this. Any thoughts?

[mvanhorn]

Good question. A few thoughts:

1. The existing cleanup dry-run already shows what would be removed before --force is used, so there's a built-in safety net. This matches how formulae/casks work today.

2. Flatpak and VSCode extensions already follow this same pattern -- cleanup lists them, --force removes them. npm/cargo/go/uv are consistent with that.

3. If you'd prefer an extra guardrail, one option would be a --skip-type flag (or env var like HOMEBREW_BUNDLE_CLEANUP_SKIP_TYPES) so users can opt specific extension types out of cleanup. Happy to add that if you think it's worth it.

Open to other ideas too.