feat(D-01/C): consumer migration — 85 files migrated to V2 helpers

Phase 1 (state): PlayerBindState, PlayerCaptorManager, PlayerEquipment,
  PlayerDataRetrieval, PlayerLifecycle, PlayerShockCollar, StruggleAccessory
Phase 2 (client): AnimationTickHandler, NpcAnimationTickHandler, 5 render
  handlers, DamselModel, 3 client mixins, SelfBondageInputHandler,
  SlaveManagementScreen, ActionPanel, SlaveEntryWidget, ModKeybindings
Phase 3 (entities): 28 entity/AI files migrated to CollarHelper,
  BindModeHelper, PoseTypeHelper, createStack()
Phase 4 (network): PacketSlaveAction, PacketMasterEquip,
  PacketAssignCellToCollar, PacketNpcCommand, PacketFurnitureForcemount
Phase 5 (events): RestraintTaskTickHandler, PetPlayRestrictionHandler,
  PlayerEnslavementHandler, ChatEventHandler, LaborAttackPunishmentHandler
Phase 6 (commands): BondageSubCommand, CollarCommand, NPCCommand,
  KidnapSetCommand
Phase 7 (compat): MCAKidnappedAdapter, MCA mixins
Phase 8 (misc): GagTalkManager, PetRequestManager, HangingCagePiece,
  BondageItemBlockEntity, TrappedChestBlockEntity, DispenserBehaviors,
  BondageItemLoaderUtility, RestraintApplicator, StruggleSessionManager,
  MovementStyleResolver, CampLifecycleManager

Some files retain dual V1/V2 checks (instanceof V1 || V2Helper) for
coexistence — V1-only branches removed in Branch D.

src/main/java/com/tiedup/remake/v2/furniture/network/PacketFurnitureForcemount.java

@@ -1,8 +1,8 @@
 package com.tiedup.remake.v2.furniture.network;
 
 import com.tiedup.remake.core.TiedUpMod;
-import com.tiedup.remake.items.base.ItemCollar;
 import com.tiedup.remake.network.PacketRateLimiter;
+import com.tiedup.remake.v2.bondage.CollarHelper;
 import com.tiedup.remake.state.IBondageState;
 import com.tiedup.remake.util.KidnappedHelper;
 import com.tiedup.remake.v2.BodyRegionV2;
@@ -28,7 +28,7 @@ import net.minecraftforge.network.NetworkEvent;
  * Client-to-server packet: master forces a captive onto a furniture seat.
  *
  * <p>The sender must own the captive's collar (verified via
- * {@link ItemCollar#isOwner(ItemStack, net.minecraft.world.entity.player.Player)}),
+ * {@link CollarHelper#isOwner(ItemStack, net.minecraft.world.entity.player.Player)}),
  * the captive must be alive and within 5 blocks of both sender and furniture,
  * and the furniture must have an available seat.</p>
  *
@@ -132,10 +132,7 @@ public class PacketFurnitureForcemount {
         }
 
         ItemStack collarStack = captiveState.getEquipment(BodyRegionV2.NECK);
-        if (
-            collarStack.isEmpty() ||
-            !(collarStack.getItem() instanceof ItemCollar collar)
-        ) {
+        if (!CollarHelper.isCollar(collarStack)) {
             TiedUpMod.LOGGER.debug(
                 "[PacketFurnitureForcemount] Invalid collar item on captive"
             );
@@ -143,7 +140,7 @@ public class PacketFurnitureForcemount {
         }
 
         // Collar must be owned by sender (or sender has admin permission)
-        if (!collar.isOwner(collarStack, sender) && !sender.hasPermissions(2)) {
+        if (!CollarHelper.isOwner(collarStack, sender) && !sender.hasPermissions(2)) {
             TiedUpMod.LOGGER.debug(
                 "[PacketFurnitureForcemount] {} is not the collar owner of {}",
                 sender.getName().getString(),