fix(release): inject tag version into binaries

[JSONbored]

Summary

• make the CLI version variable linker-overridable
• inject GoReleaser .Version into both nightward and nw binaries

What changed

• changed internal/cli.version from a constant to a variable so -X can override it
• added matching GoReleaser ldflags for both released binaries

Why

• the release smoke correctly caught that immutable v0.1.2 binaries still reported 0.1.0
• npm publishing depends on the release archive smoke passing first

Validation

• go test ./internal/cli
• go run -ldflags '-X github.com/jsonbored/nightward/internal/cli.version=9.8.7-test' ./cmd/nightward --version
• go run -ldflags '-X github.com/jsonbored/nightward/internal/cli.version=9.8.7-test' ./cmd/nw --version
• go run github.com/goreleaser/goreleaser/v2@v2.9.0 check
• git diff --check
• make release-snapshot
• extracted dist/nightward_0.1.2-SNAPSHOT-76b8a3c_darwin_arm64.tar.gz and verified both binaries print 0.1.2-SNAPSHOT-76b8a3c

Notes

• After merge, cut a new signed patch tag because the immutable v0.1.2 release already exists with binaries that report 0.1.0.