P3-11 review followup : isolate client-only handler behind @OnlyIn

Prepare P3-12 consumption of Minecraft.getInstance() — refactor
handleOnClient() to delegate into a private ClientHandler inner class
annotated @OnlyIn(Dist.CLIENT). Server-side class-loader will not
resolve Minecraft.* references since the inner class isn't touched.

Direction guard inchangé. Import NetworkDirection passé top-level.

Issue : review transversale Phase 3 (architect agent), recommendation #3.

src/main/java/com/tiedup/remake/rig/network/PacketPlayRigAnim.java

@@ -8,6 +8,9 @@ import java.util.function.Supplier;
 
 import net.minecraft.network.FriendlyByteBuf;
 import net.minecraft.resources.ResourceLocation;
+import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.api.distmarker.OnlyIn;
+import net.minecraftforge.network.NetworkDirection;
 import net.minecraftforge.network.NetworkEvent;
 
 import com.tiedup.remake.rig.TiedUpRigConstants;
@@ -77,6 +80,10 @@ public record PacketPlayRigAnim(
     /**
      * Handler client — stub P3-11. Le corps complet (resolve entity, lookup
      * patch, playAnimation) viendra en P3-12.
+     *
+     * <p>La logique client-only est isolée dans {@link ClientHandler} pour que
+     * le classloader serveur ne résolve jamais {@code Minecraft.*} (sera
+     * référencé en P3-12). Voir review transversale Phase 3 (reco #3).
      */
     public static void handleOnClient(PacketPlayRigAnim pkt, Supplier<NetworkEvent.Context> ctx) {
         NetworkEvent.Context context = ctx.get();
@@ -85,7 +92,7 @@ public record PacketPlayRigAnim(
         // n'enforce pas NetworkDirection, donc un client malveillant pourrait
         // spoofer ce packet vers le serveur. Guard défensif (voir P3-11 review
         // RISK-001 — fix systémique du helper reg() tracé en backlog séparé).
-        if (context.getDirection() != net.minecraftforge.network.NetworkDirection.PLAY_TO_CLIENT) {
+        if (context.getDirection() != NetworkDirection.PLAY_TO_CLIENT) {
             TiedUpRigConstants.LOGGER.warn(
                 "[PacketPlayRigAnim] rejected non-S→C packet direction: {} (possible spoofing attempt)",
                 context.getDirection()
@@ -94,13 +101,29 @@ public record PacketPlayRigAnim(
             return;
         }
 
-        context.enqueueWork(() -> {
+        // Délégation client-only. L'inner class n'est class-loadée que si cette
+        // branche s'exécute, donc safe côté serveur même si Minecraft.* y est
+        // référencé en P3-12.
+        context.enqueueWork(() -> ClientHandler.apply(pkt));
+        context.setPacketHandled(true);
+    }
+
+    /**
+     * Handler client-only. Encapsule toute dépendance {@code Minecraft.*} pour
+     * éviter un NoClassDefFoundError serveur-side si la JVM resolve les refs
+     * dist-only du handler principal.
+     */
+    private static final class ClientHandler {
+        private ClientHandler() {}
+
+        @OnlyIn(Dist.CLIENT)
+        static void apply(PacketPlayRigAnim pkt) {
             TiedUpRigConstants.LOGGER.debug(
                 "[PacketPlayRigAnim] received (stub P3-11): entityId={}, animId={}, transition={}s, priority={}",
                 pkt.entityId, pkt.animId, pkt.transitionTime, pkt.priority()
             );
-            // TODO P3-12 : resolve entity + patch + animator.playAnimation
+            // TODO P3-12 : Minecraft.getInstance().level.getEntity(pkt.entityId())
-        });
+            //              + LivingEntityPatch lookup + animator.playAnimation
-        context.setPacketHandled(true);
+        }
     }
 }