Publish and maintain the independent public fork #9

Problem

The public fork has eight focused upstream contributions, but its default branch still matches the original project. People need a usable maintained version with clear attribution, issue/PR traceability, and CI that does not depend on Google's internal accounts and publishing setup.

Planned result

• Integrate the reviewed Docs workflow improvements and Clippy prerequisite into this fork's main through a fork-local PR.
• Preserve the native GitHub fork relationship, original history, authors, and Apache-2.0 license; clearly identify ratovarius as this fork's maintainer.
• Document source installation, the feature/upstream PR ledger, contributing here, offering focused changes upstream, and safely importing upstream changes.
• Keep a pristine upstream-main branch and retain the focused branches backing open upstream PRs.
• Use read-only Linux/macOS Rust and Python CI with synthetic fixtures. Archive inherited Google-specific automation and document the initial coverage limits.
• Preserve the eight upstream PRs for community review while development continues here. No registry packages are published as part of this source publication.

Related work

Acceptance

• README and repository metadata make the fork identity clear.
• All improvements are available on fork main, with issues and upstream PRs linked.
• Fresh local test/lint/build checks and independent review pass.
• Fork CI runs without Google account secrets.
• A fork-local publication PR documents and merges the result.

Published through #10 at commit a25acfc6ffda1b9b46879dd498c795598078276f. All nine fork issues are closed; upstream PRs googleworkspace#930–937 remain open. The seven maintained PR checks passed on GitHub. See FORK.md and CONTRIBUTING.md on main for the feature ledger and contribution flow.