Initial Fabric mod for chat-based quiz answer submission

Hooks ServerMessageEvents.ALLOW_CHAT_MESSAGE to intercept chat while the
music_quiz datapack is in answer-accepting state (init=5 on objective
'main'). Intercepted messages are forwarded to mq:answer/submit with the
player's UUID context and the chat broadcast is suppressed so the answer
stays hidden from other players. Outside that state chat passes through
normally.

Target: Minecraft 1.21.6+, Java 21, Fabric Loader 0.16+, Fabric API.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

build.gradle

@@ -0,0 +1,45 @@
+plugins {
+    id 'fabric-loom' version '1.10-SNAPSHOT'
+    id 'java'
+}
+
+group = project.mod_group
+version = project.mod_version
+archivesBaseName = project.mod_id
+
+java {
+    toolchain.languageVersion = JavaLanguageVersion.of(21)
+    withSourcesJar()
+}
+
+repositories {
+    maven { url = 'https://maven.fabricmc.net/' }
+    mavenCentral()
+}
+
+dependencies {
+    minecraft "com.mojang:minecraft:${project.minecraft_version}"
+    mappings "net.fabricmc:yarn:${project.yarn_mappings}:v2"
+    modImplementation "net.fabricmc:fabric-loader:${project.loader_version}"
+    modImplementation "net.fabricmc.fabric-api:fabric-api:${project.fabric_version}"
+}
+
+processResources {
+    inputs.property "version", project.version
+    inputs.property "mod_id", project.mod_id
+
+    filesMatching("fabric.mod.json") {
+        expand "version": project.version, "mod_id": project.mod_id
+    }
+}
+
+tasks.withType(JavaCompile).configureEach {
+    options.release = 21
+    options.encoding = 'UTF-8'
+}
+
+jar {
+    from("LICENSE") {
+        rename { "${it}_${project.archivesBaseName}" }
+    }
+}