P3-11 : add PacketPlayRigAnim + ModNetwork registration (handler stub)

Record packet S->C pour animations cinematic one-shot (capture NPC, hit
stun, death). Carries entityId, animId (ResourceLocation), transitionTime
(float), et priorityOrdinal (byte = Layer.Priority.ordinal()).

Encode via writeVarInt/writeResourceLocation/writeFloat/writeByte ; decode
symétrique. Factory PacketPlayRigAnim.of() pour build lisible avec
Layer.Priority, et getter priority() avec fallback LOWEST si ordinal
hors-range (masking & 0xFF pour gérer byte négatif).

Handler client = stub qui LOGGER.debug + setPacketHandled. Le corps
complet (resolve entity, lookup LivingEntityPatch, animator.playAnimation)
viendra en P3-12 avec la méthode serveur playAnimationSync().

Registration ajoutée en fin de ModNetwork.register() — ID sequential 75
(76 packets total).

7 tests unitaires PacketPlayRigAnimTest : roundtrip nominal, entityId
boundary (0/MAX/MIN), transitionTime zero+negative (pas de validation
silencieuse), loop sur les 5 Layer.Priority, fallback LOWEST sur ordinal
malformé (99, -1, PRIORITY_COUNT), ResourceLocation avec underscores et
slashes, et sanity check equals.

Rig tests : 65 -> 72 GREEN. Full suite : 162 GREEN, 0 failure.

src/main/java/com/tiedup/remake/network/ModNetwork.java

@@ -64,6 +64,7 @@ import com.tiedup.remake.network.sync.PacketSyncPetBedState;
 import com.tiedup.remake.network.sync.PacketSyncStruggleState;
 import com.tiedup.remake.network.trader.PacketBuyCaptive;
 import com.tiedup.remake.network.trader.PacketOpenTraderScreen;
+import com.tiedup.remake.rig.network.PacketPlayRigAnim;
 import com.tiedup.remake.v2.bondage.network.PacketSyncV2Equipment;
 import com.tiedup.remake.v2.bondage.network.PacketV2LockToggle;
 import com.tiedup.remake.v2.bondage.network.PacketV2SelfEquip;
@@ -592,6 +593,14 @@ public class ModNetwork {
             PacketSyncMovementStyle::handle
         );
 
+        // RIG animation system (S2C cinematic one-shot)
+        reg(
+            PacketPlayRigAnim.class,
+            PacketPlayRigAnim::encode,
+            PacketPlayRigAnim::decode,
+            PacketPlayRigAnim::handleOnClient
+        );
+
         TiedUpMod.LOGGER.info("Registered {} network packets", packetId);
     }