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]>

gradle/gitea.gradle.kts

@@ -0,0 +1,17 @@
+// Shared publishing target: the saturnclientmc org's Maven registry on Gitea.
+// Publish with a token that has package:write:  GITEA_TOKEN=... ./gradlew publish
+configure<PublishingExtension> {
+    repositories {
+        maven {
+            name = "Gitea"
+            url = uri("https://git.selimaj.dev/api/packages/saturnclientmc/maven")
+            credentials(HttpHeaderCredentials::class) {
+                name = "Authorization"
+                value = "token ${findProperty("giteaToken") ?: System.getenv("GITEA_TOKEN") ?: ""}"
+            }
+            authentication {
+                create<HttpHeaderAuthentication>("header")
+            }
+        }
+    }
+}