* ci(release): add goreleaser and semver configuration
The release builds only cmd/readitall for Linux, macOS and Windows on amd64 and arm64. The checksum file is signed with cosign. The semver config uses regex matching. A major release needs an explicit trailer line.
* ci: add shared pull request, release and autoupdate workflows
The workflows call the shared workflows in lukaszraczylo/shared-actions. The release runs on push to main when Go files change.
* docs: describe release binary installation
The README now tells you to download a binary from the GitHub release page.
* fix(browser): remove the unused mutex field of SessionStore
Staticcheck reports U1000 for the field. No method locks it. The
pull request checks fail until the field is removed.