add cargo-binstall metadata

[abra3607]

Adds [package.metadata.binstall] to Cargo.toml so cargo binstall workmux resolves the existing goreleaser release artifacts instead of falling back to a source compile.

Why

Without this metadata, binstall expects asset names like workmux-x86_64-unknown-linux-gnu.tar.gz, but the goreleaser pipeline publishes workmux-linux-amd64.tar.gz (etc.). The mismatch makes binstall fall through to cargo install, which compiles from source — slow, and requires a full Rust toolchain in user environments (Docker images, CI) that only wanted a binary.

The release assets users want already exist; this just teaches binstall where to find them.

What

Maps each supported Rust target triple to the matching goreleaser asset:

target triple	asset
x86_64-unknown-linux-{gnu,musl}	workmux-linux-amd64.tar.gz
aarch64-unknown-linux-{gnu,musl}	workmux-linux-arm64.tar.gz
x86_64-apple-darwin	workmux-darwin-amd64.tar.gz
aarch64-apple-darwin	workmux-darwin-arm64.tar.gz

Pure metadata change — no CI, release pipeline, or version bump. No new release targets added; this only points binstall at what's already published.

The musl overrides reuse the gnu-built asset since the binary is statically-linked-enough in practice; happy to drop them if you'd rather only advertise gnu.

Verification

Tested against v0.1.183 from a local checkout with the patched Cargo.toml:

$ cargo binstall --manifest-path ./Cargo.toml --dry-run --targets x86_64-unknown-linux-gnu workmux
 INFO resolve: Resolving package: 'workmux'
 WARN The package workmux v0.1.183 (x86_64-unknown-linux-gnu) has been downloaded from github.com
 INFO This will install the following binaries:
 INFO   - workmux => /root/.cargo/bin/workmux

Resolved URL: https://github.com/raine/workmux/releases/download/v0.1.183/workmux-linux-amd64.tar.gz. Confirmed the same for aarch64-unknown-linux-{gnu,musl}, x86_64-unknown-linux-musl, x86_64-apple-darwin, and aarch64-apple-darwin. End-to-end install into a throwaway dir extracts the binary at the archive root and workmux --version prints workmux 0.1.183.

References

• binstall metadata reference: https://github.com/cargo-bins/cargo-binstall/blob/main/SUPPORT.md

[raine]

Thanks