Scaffold the emote library with a Stonecutter Fabric mod and tester

- core/: Minecraft-independent animation model (Bone, BoneTransform with
  bend fields, Pose, Animation, AnimationPlayer) with JUnit tests.
- src/main: Fabric mod built for 1.21.4-1.21.11 with Stonecutter on
  Mojang mappings. Samples each player's pose into its render state and
  applies it at the end of HumanoidModel.setupAnim (armor follows too).
- src/testmod: dev-only tester with /emotes play|stop|info and a mixin
  audit on startup.
- Publishing to the saturnclientmc Gitea Maven registry as
  org.saturnclient:emotes-core and emotes-fabric:<v>+<mc>.

Loom is pinned to 1.17 because 1.18 needs a Java 25 JVM.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

.gitignore

@@ -1,26 +1,40 @@
-# ---> Java
-# Compiled class file
-*.class
+# gradle
 
-# Log file
-*.log
+.gradle/
+build/
+out/
+classes/
 
-# BlueJ files
-*.ctxt
+# eclipse
 
-# Mobile Tools for Java (J2ME)
-.mtj.tmp/
+*.launch
 
-# Package Files #
-*.jar
-*.war
-*.nar
-*.ear
-*.zip
-*.tar.gz
-*.rar
+# idea
 
-# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
-hs_err_pid*
-replay_pid*
+.idea/
+*.iml
+*.ipr
+*.iws
 
+# vscode
+
+.settings/
+.vscode/
+bin/
+.classpath
+.project
+
+# macos
+
+*.DS_Store
+
+# fabric
+
+run/
+
+# java
+
+hs_err_*.log
+replay_*.log
+*.hprof
+*.jfr