LOD Server Support

• Add mavenCentral() to fabric repositories for CI dependency resolution
• Merge branch 'mc-26.1-multiversion' — Fabric MC 26.1 update (v0.3.0)
• Target MC 26.1.2, list all 26.1.x versions on Modrinth
• Accept MC 26.1.x hotfix releases in fabric.mod.json
• Use quadratic curve for vanilla chunk load throttling
• Fix broken Java version check in test-server.sh, restore lost comment
• Update Fabric mod to Minecraft 26.1, Fabric-only v0.3.0 release
• Extract release notes from annotated tags for GitHub and Modrinth releases

Full Changelog: https://github.com/VoX/lod-server-support/compare/v0.2.3...v0.3.0