Migrate CI from Cirrus CI to GitHub Actions

[fkorotkov-oai]

What changed

• replace Cirrus CI lint and macOS test jobs with GitHub Actions
• move tag and dry-run releases to GoReleaser Pro
• remove Sentry release side effects

Release setup

Before the next release, configure GORELEASER_KEY and GH_PAT as repository secrets. GH_PAT needs write access to cirruslabs/homebrew-cli.

Validation

• actionlint
• goreleaser check --soft with GoReleaser Pro 2.16.0
• cargo fmt --check
• cargo clippy --all-targets --all-features -- -D warnings

cargo test built successfully and reached the test binary, which requires passwordless sudo; the migrated test jobs run on the configured macOS runners.