LinguaChat

feat: add multi-version support with Stonecutter and release automation

• Add Stonecutter plugin for building across 8 Minecraft versions (1.16.5 - 1.21.11)
• Configure version-specific dependencies (Fabric API, Mod Menu, Java toolchain)
• Add compatibility layers (TextCompat, ScreenCompat, ButtonCompat, I18nCompat, KeyBindingCompat)
• Add Kagi translation provider alongside existing Google Translate and DeepL
• Add configuration GUI with ConfigScreen and ModMenu integration
• Add keybind support for toggling translation and opening config screen
• Add translation caching, logging, and message store API
• Add GitHub Actions workflows for build and release with manual approval
• Add developer documentation (EN/RU)
• Update mod version to 2.0.0
• Remove unused Forge mods.toml and hardcoded Java path from gradle.properties