ci: update Homebrew tap on release

[dinakars777]

Adds an update-homebrew-tap job that dispatches the centralized formula updater in steipete/homebrew-tap after a successful release. Uses gh run watch for synchronous failure visibility.

Depends on steipete/homebrew-tap#29

Required secret: HOMEBREW_TAP_TOKEN with workflow dispatch access to steipete/homebrew-tap.

[steipete]

Thanks @dinakars777. Current main already contains the tap automation from this PR, and I verified it against the current release/tap contract:

• .github/workflows/release.yml dispatches steipete/homebrew-tap/.github/workflows/update-formula.yml with formula=blucli, repository=steipete/blucli, and macos_artifact=blucli-macos-arm64.tar.gz.
• Latest steipete/blucli release v0.1.3 contains blucli-macos-arm64.tar.gz.
• homebrew-tap/Formula/blucli.rb currently points at that same asset.

While reviewing this, I found and fixed a separate release-blocker in #2: current GoReleaser rejects deprecated archive fields, and CI govulncheck needed the Go 1.25.10 toolchain. #2 is merged with all CI runs green. Closing this PR as superseded by current main + #2.