add release workflow

[zfdang]

This pull request introduces a new GitHub Actions workflow for automating releases when a tag is pushed to the repository. The workflow ensures releases are only created for tags that point to commits on the main branch, sets up the necessary Rust and zero-knowledge toolchains, builds the project, prepares release artifacts, and publishes them to GitHub Releases.

Release automation:

• Added a new workflow file .github/workflows/release.yml to automate building and publishing releases when a tag is pushed.
• The workflow checks that the tag points to a commit on origin/main before proceeding with the release, ensuring only mainline commits are released.

Toolchain setup:

• Installs the stable Rust toolchain, RISC0 toolchain (rzup), and SP1 toolchain (sp1up) for building and verifying zero-knowledge proofs.

Build and release process:

• Builds the project in release mode, packages the binary as a tarball, and uploads it as a release asset to GitHub Releases.