feat(M1): Fabric scaffold for MC 1.21.6 with /videoStick

- video_player mod id, 영상재생모드 display name
- VideoAnchorBlock + VideoAnchorBlockEntity (placeholder)
- VideoStickItem
- /videoStick (+ /videostick alias) command gives the stick
- gradle 9.5.1 wrapper, fabric-loom 1.16.2, Java 21 toolchain
- works in both singleplayer and dedicated server (environment: *)

gradle.properties

@@ -0,0 +1,14 @@
+org.gradle.jvmargs=-Xmx2G
+org.gradle.parallel=true
+
+# Mod
+mod_id=video_player
+mod_version=0.1.0
+maven_group=com.ejclaw.videoplayer
+archives_base_name=video_player
+
+# Minecraft / Fabric (1.21.6)
+minecraft_version=1.21.6
+yarn_mappings=1.21.6+build.1
+loader_version=0.19.2
+fabric_version=0.120.1+1.21.6