Introduces new matthiesen-lib-api package for server-friendly projects

[Adammatthiesen]

This pull request introduces a major refactor and migration of the Matthiesen Lib project, splitting it into two distinct mods: matthiesen-lib-api (server-side API) and matthiesen-lib (full server/client mod). It also overhauls the CI/CD workflow to support multi-project publishing, dependency management, and improved release automation. Extensive developer documentation is provided to aid migration and clarify the new project structure.

Project Structure & Documentation Updates:

• Added a new api/README.md describing the purpose and usage of the matthiesen-lib-api mod, and updated the root README.md to explain the split between API and Lib mods, including setup instructions for developers using Loom. [1] [2]
• Introduced a comprehensive DEV-DOCS.md detailing the migration, new module structure, API/lib separation, and compatibility strategies for developers.

Build & Workflow Overhaul:

• Removed the old monolithic build workflow (.github/workflows/build.yml) and replaced it with a snapshot PR workflow (pr-snapshot.yml) and a much more sophisticated release workflow (publish-release.yml). These workflows now handle building, publishing, dependency resolution, Modrinth uploads for both API and Lib, and Discord notifications. [1] [2] [3] [4] [5] [6] [7]

Dependency & Publishing Improvements:

• The release workflow now dynamically constructs Modrinth dependency lists per project and loader, supports multi-platform (Fabric/NeoForge) and multi-module (API/Lib) publishing, and synchronizes project descriptions from the correct README files. [1] [2] [3]
• Added a new Gradle build script for the API common module (api/common/build.gradle.kts) with correct dependencies, resource processing, and plugin setup.

Release Automation & Notifications:

• Automated Discord notifications for new releases, with embeds containing version, platform, and links to Modrinth and GitHub releases.

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Most Important Changes:

1. Project Structure & Migration

• Split the codebase into two mods: matthiesen-lib-api (API-only, server-side) and matthiesen-lib (full mod, includes API as a required dependency), with dedicated documentation and migration notes for developers. [1] [2] [3]

2. Build & CI/CD Workflow

• Replaced the old build workflow with new PR snapshot and release workflows, supporting multi-module, multi-platform builds, artifact publishing, and dependency management for both mods. [1] [2] [3] [4] [5] [6]

3. Publishing & Dependency Management

• Improved release automation: builds are published to Modrinth for both API and Lib (Fabric/NeoForge), with dynamically generated dependencies and project metadata. [1] [2] [3] [4]

4. Release Notifications

• Added Discord webhook notifications for new releases, with detailed embeds for each published project.

5. Developer Experience

• Added developer documentation (DEV-DOCS.md) and improved setup instructions, including a bootstrap script for fresh clones and detailed migration notes. [1] [2]

This refactor lays the foundation for a more maintainable, modular, and developer-friendly Matthiesen Lib ecosystem.