feat(release): add one-click release workflow

[Teakowa]

Summary

Implements one-click, versioned GitHub Actions releases for workshop-rs.

• Adds a manual Release workflow with patch, minor, and major bump choices.
• Computes and mutates the workspace version, publishable CLI dependency version, and Cargo.lock together.
• Runs fmt, clippy, tests, catalog validation, and package verification before publication.
• Commits the deterministic release metadata, pushes the immutable vX.Y.Z tag, and publishes workshop-rs before workshop-rs-cli.
• Builds Linux x86_64/aarch64, macOS x86_64/aarch64, and Windows x86_64 CLI archives with SHA256SUMS.txt.
• Creates a draft GitHub Release, attaches artifacts and generated notes with revision/catalog identity, then publishes it only after all required jobs succeed.
• Resumes incomplete releases without silently bumping versions or duplicating published crates/artifacts.
• Documents the protected release environment, CARGO_REGISTRY_TOKEN, permissions, and main-branch release exception.

The CLI keeps its local path dependency for development while declaring the matching registry version required for publication.

Closes #14.

Validation

• python3 scripts/test_release.py — 6 passed
• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/release.yml")'
• cargo fmt --all --check
• cargo clippy --locked --workspace --all-targets -- -D warnings
• cargo test --locked --workspace --all-targets
• cargo run --locked -p workshop-rs --bin workshop-catalog-gen -- check
• Rust 1.85.0: fmt, clippy, tests, and catalog check passed
• cargo package / cargo publish --dry-run passed for both packages with a temporary local registry patch; the real workflow verifies the CLI after the library is visible on crates.io.