Modernize project: migrate to net.blockhost, add CI, metadata, and docs

- Migrate package from me.itskronx11 to net.blockhost across all modules
- Add MIT LICENSE and rewrite README with badges, features, and build instructions
- Add GitHub Actions CI (build.yml) and release automation (release.yml)
- Migrate MC module build files from Groovy to Kotlin DSL (build.gradle.kts)
- Update fabric.mod.json with proper metadata, contact info, and java >=21 dep
- Remove unused fabricApi configureDataGeneration block
- Add .editorconfig and root gradle.properties for shared config
- Set GitHub repo description

Co-Authored-By: Claude Opus 4.6 <[email protected]>

mc-1.21.9/src/main/java/net/blockhost/anarchymod/JoinPayload.java

@@ -0,0 +1,25 @@
+package net.blockhost.anarchymod;
+
+import net.minecraft.network.FriendlyByteBuf;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
+import net.minecraft.resources.ResourceLocation;
+
+public class JoinPayload implements CustomPacketPayload {
+
+    public static final ResourceLocation ID = ResourceLocation.fromNamespaceAndPath("anarchymod", "join");
+
+    public static final StreamCodec<FriendlyByteBuf, JoinPayload> CODEC =
+            StreamCodec.of(
+                    (payload, buf) -> {},
+                    buf -> new JoinPayload()
+            );
+
+    public static final Type<JoinPayload> TYPE =
+            new Type<>(ID);
+
+    @Override
+    public Type<? extends CustomPacketPayload> type() {
+        return TYPE;
+    }
+}