doc: Migrate docs to mdBook, slim down the readme

[philiplinden]

Highlights

• Turns on git-cliff powered Changelog generation
• Migrates most of the documentation from README.md to doc/book/src
• Adds CI workflow that builds a site from the docs with mdBook and deploys it to GitHub Pages.

Copilot Summary

This pull request introduces several improvements focused on documentation, changelog automation, and build configuration for the Bevy REPL project. The most significant changes include adding a comprehensive mdBook documentation workflow, updating changelog generation and formatting, and refining Cargo features and dependencies.

Documentation and Build Automation:

• Added a GitHub Actions workflow (.github/workflows/mdbook.yml) to build and deploy the mdBook documentation to GitHub Pages on tagged releases, including caching and plugin setup for efficient builds.
• Created book.toml to configure mdBook settings, output directory, preprocessors, and site URLs for proper documentation rendering and deployment.
• Added extensive documentation structure in doc/src/SUMMARY.md and new content files covering features, commands, configuration, design, and development topics. [1] [2] [3] [4] [5] [6] [7]

Changelog and Release Management:

• Updated changelog workflow triggers in .github/workflows/changelog.yml to run on pull requests to main and pushes to tags, ignoring changes to CHANGELOG.md.
• Refined changelog formatting and generation in cliff.toml: improved header/footer, contributor listing, tag patterns, and repository references. [1] [2] [3] [4] [5] [6]
• Updated CHANGELOG.md to reference GitHub Releases and the new documentation site, and improved contributor formatting. [1] [2]

Cargo Features and Dependency Updates:

• Bumped crate version to 0.4.1 and updated clap dependency to 4.5.46 in Cargo.toml. [1] [2]
• Modified default features to include both quit and help commands by default.

These changes collectively improve the project's documentation, automate release and changelog management, and ensure up-to-date dependencies and feature flags for users and contributors.

[github-actions]

Changelog

See GitHub Releases and
the Bevy REPL Book for details.

0.3.1 - 2025-08-28

📚 Documentation

• Add mdbook plugins (9b8ebd4)
• Introducing the Bevy REPL Book (b7710e0)
• Update readme toc (e4390a3)
• Update readme (43493fc)
• Add docs for other design experiments (b1b2abc)

🧪 Experimental

• Add placeholders for help (4354571)
• Remove scrollreadyset, always stdout (bed7d47)
• Move stdout behind feature flag (a6460bc)
• Make context mgmt better (8b0db88)
• Remove pretty stuff (ce50975)

⚙️ Repository

• (docs) Build mdBook on PR, deploy only on tags using mdBook action (2e090cd)
• Enable changelog generation (82832ca)

📜 Full Changelog

Changelog

See GitHub Releases and
the Bevy REPL Book for details.

[0.3.0] - 2025-08-14

📚 Documentation

• Update readme (a958b70)
• Add demo tape to readme (ce5a626)
• Readability updates (55104ba)
• Fancy demo (a328508)
• Limitations (69b39fb)
• Add known issues to readme (3a7dbe1)

🐛 Bug Fixes

• Disable the changelog for now (ca1d368)
• Clean up examples (3f6f234)
• Bad plugin setup (a1ebbe2)
• Close and quit were misconfigured (df104b1)
• Remove broken cmds that need world access (19aca25)

🧪 Experimental

• Disable changelog on main for now (9b02990)
• Demo (a1ff6b3)
• Custom log layer (bd50098)
• Pretty renderer is working (3cd37cd)
• Repl println macro (a7bb78f)
• Lots of examples and ergonomic renderer settings (7e3cbee)
• Custom renderer (ca17531)
• Even more examples (e70cf98)
• Overhaul (d0bbea2)
• Works with windowed apps too! (955262b)
• Built-in commands, derive, and examples (a781f21)
• Add more examples (d455679)
• Command parsing works!!!! (a7edc34)
• Buffer text input and backspace (d9df188)
• Custom ratatui context (fc6bba4)
• Drop bevy_crossterm and use bevy_ratatui (60231d1)
• Bevy_crossterm and simplify (2c8295e)
• Switch from rustyline to crossterm (3bda182)
• Tweaking the derive macros (ad8421b)
• Cleanup (b331b52)
• Derive (2ed17bc)
• More advanced patterns (4df61ee)
• More designing through the readme (0f7432b)
• Add rustyline, write out design docs (fd4ea0f)

New Contributors ❤️

• @philiplinden made their first contribution