Refactor V2 animation, furniture, and GLTF rendering

Broad consolidation of the V2 bondage-item, furniture-entity, and
client-side GLTF pipeline.

Parsing and rendering
  - Shared GLB parsing helpers consolidated into GlbParserUtils
    (accessor reads, weight normalization, joint-index clamping,
    coordinate-space conversion, animation parse, primitive loop).
  - Grow-on-demand Matrix4f[] scratch pool in GltfSkinningEngine and
    GltfLiveBoneReader — removes per-frame joint-matrix allocation
    from the render hot path.
  - emitVertex helper dedups three parallel loops in GltfMeshRenderer.
  - TintColorResolver.resolve has a zero-alloc path when the item
    declares no tint channels.
  - itemAnimCache bounded to 256 entries (access-order LRU) with
    atomic get-or-compute under the map's monitor.

Animation correctness
  - First-in-joint-order wins when body and torso both map to the
    same PlayerAnimator slot; duplicate writes log a single WARN.
  - Multi-item composites honor the FullX / FullHeadX opt-in that
    the single-item path already recognized.
  - Seat transforms converted to Minecraft model-def space so
    asymmetric furniture renders passengers at the correct offset.
  - GlbValidator: IBM count / type / presence, JOINTS_0 presence,
    animation channel target validation, multi-skin support.

Furniture correctness and anti-exploit
  - Seat assignment synced via SynchedEntityData (server is
    authoritative; eliminates client-server divergence on multi-seat).
  - Force-mount authorization requires same dimension and a free
    seat; cross-dimension distance checks rejected.
  - Reconnection on login checks for seat takeover before re-mount
    and force-loads the target chunk for cross-dimension cases.
  - tiedup_furniture_lockpick_ctx carries a session UUID nonce so
    stale context can't misroute a body-item lockpick.
  - tiedup_locked_furniture survives death without keepInventory
    (Forge 1.20.1 does not auto-copy persistent data on respawn).

Lifecycle and memory
  - EntityCleanupHandler fans EntityLeaveLevelEvent out to every
    per-entity state map on the client.
  - DogPoseRenderHandler re-keyed by UUID (stable across dimension
    change; entity int ids are recycled).
  - PetBedRenderHandler, PlayerArmHideEventHandler, and
    HeldItemHideHandler use receiveCanceled + sentinel sets so
    Pre-time mutations are restored even when a downstream handler
    cancels the render.

Tests
  - JUnit harness with 76+ tests across GlbParserUtils, GltfPoseConverter,
    FurnitureSeatGeometry, and FurnitureAuthPredicate.

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

@@ -103,9 +103,10 @@ public class NetworkEventHandler {
             ModNetwork.sendToPlayer(enslavementPacket, tracker);
         }
 
-        // FIX MC-262715: Explicitly sync riding state and position
-        // This fixes the "frozen player" bug when tracker reconnects after
-        // the tracked player was freed from a vehicle
+        // Workaround for MC-262715: vanilla doesn't resync riding state or
+        // position when a tracker reconnects, so a tracked player who was
+        // freed from a vehicle between the two connect events renders
+        // frozen until they next move.
         if (trackedPlayer instanceof ServerPlayer trackedServerPlayer) {
             syncRidingStateAndPosition(trackedServerPlayer, tracker);
         }
@@ -328,6 +329,16 @@ public class NetworkEventHandler {
                         return;
                     }
 
+                    // Force-load the target chunk before the search so
+                    // cross-dimension reconnects don't silently fail on an
+                    // unloaded chunk — that was a "disconnect then cross-dim
+                    // travel to escape" hole where the null-furniture path
+                    // below cleared the tag.
+                    targetLevel.getChunk(
+                        furniturePos.getX() >> 4,
+                        furniturePos.getZ() >> 4
+                    );
+
                     // Search for the furniture entity near the stored position
                     Entity furniture = findFurnitureEntity(
                         targetLevel,
@@ -384,8 +395,27 @@ public class NetworkEventHandler {
                         );
                     }
 
-                    // Re-mount the player
-                    boolean mounted = player.startRiding(furniture, true);
+                    // Re-mount the player.
+                    // If the original seat was taken (e.g. force-mounted by
+                    // another player while this one was offline), assignSeat
+                    // would overwrite the mapping and orphan the current
+                    // occupant. Teleport to the furniture position instead
+                    // and drop the tag — keeping either player in a
+                    // deterministic seat is better than a double-mount.
+                    // Uses ISeatProvider.findPassengerInSeat so future
+                    // non-EntityFurniture seat providers also benefit.
+                    boolean mounted = false;
+                    if (provider.findPassengerInSeat(seatId) != null) {
+                        TiedUpMod.LOGGER.warn(
+                            "[Network] Seat '{}' on furniture {} is now occupied by another entity; skipping reconnection for {}.",
+                            seatId,
+                            furnitureUuidStr,
+                            player.getName().getString()
+                        );
+                    } else {
+                        mounted = player.startRiding(furniture, true);
+                    }
+
                     if (mounted) {
                         provider.assignSeat(player, seatId);
                         TiedUpMod.LOGGER.info(

src/main/java/com/tiedup/remake/network/conversation/PacketEndConversationC2S.java

@@ -53,9 +53,9 @@ public class PacketEndConversationC2S {
                     damsel = d;
                 }
 
-                // Always clean up conversation state — this is a teardown packet.
-                // Distance check removed: blocking cleanup causes permanent state leak
-                // in ConversationManager.activeConversations (reviewer H18 BUG-001).
+                // Teardown must not gate on distance — the damsel may have
+                // moved out of range while the screen was open, and blocking
+                // cleanup would leak the conversation entry permanently.
                 ConversationManager.endConversation(sender, damsel);
             });
         ctx.get().setPacketHandled(true);

src/main/java/com/tiedup/remake/network/merchant/PacketCloseMerchantScreen.java

@@ -80,9 +80,9 @@ public class PacketCloseMerchantScreen {
             return;
         }
 
-        // Always clean up trading state — this is a teardown packet.
-        // Distance check removed: blocking cleanup causes permanent state leak
-        // in tradingPlayers map (reviewer H18 BUG-002).
+        // Teardown must not gate on distance — the merchant may have moved
+        // out of range while the screen was open, and blocking cleanup
+        // would permanently leak the player's entry in tradingPlayers.
         merchant.stopTrading(player.getUUID());
     }
 }

src/main/java/com/tiedup/remake/network/minigame/PacketLockpickAttempt.java

@@ -115,15 +115,22 @@ public class PacketLockpickAttempt {
         ServerPlayer player,
         LockpickMiniGameState session
     ) {
-        // Check for furniture lockpick context FIRST — if present, this is a
-        // furniture seat lockpick, not a body item lockpick. The context tag is
-        // written by PacketFurnitureEscape.handleLockpick() when starting the session.
+        // Furniture seat lockpick path: presence of furniture_id AND a
+        // session_id matching the current session. A ctx without the nonce
+        // (or with a foreign nonce) is rejected — this is the branch a
+        // stale-ctx bug could otherwise mis-route into.
         CompoundTag furnitureCtx = player
             .getPersistentData()
             .getCompound("tiedup_furniture_lockpick_ctx");
-        if (furnitureCtx != null && furnitureCtx.contains("furniture_id")) {
-            // H18: Distance check BEFORE ending session — prevents consuming session
-            // without reward if player moved away (reviewer H18 RISK-001)
+        boolean ctxValid =
+            furnitureCtx != null
+            && furnitureCtx.contains("furniture_id")
+            && furnitureCtx.hasUUID("session_id")
+            && furnitureCtx.getUUID("session_id").equals(session.getSessionId());
+        if (ctxValid) {
+            // Distance check BEFORE endLockpickSession — consuming a
+            // session without applying the reward (player walked away)
+            // would burn the session with no visible effect.
             int furnitureId = furnitureCtx.getInt("furniture_id");
             Entity furnitureEntity = player.level().getEntity(furnitureId);
             if (
@@ -320,13 +327,16 @@ public class PacketLockpickAttempt {
         }
         session.setRemainingUses(remainingUses);
 
-        // Check for JAM (5% chance on miss) — only applies to body item lockpick sessions.
-        // Furniture seat locks do not have a jam mechanic (there is no ILockable item to jam).
+        // Jam mechanic (5%) only applies to body-item sessions — seat locks
+        // have no ILockable stack to jam.
         boolean jammed = false;
-        boolean isFurnitureSession = player
+        CompoundTag sessionCtx = player
             .getPersistentData()
-            .getCompound("tiedup_furniture_lockpick_ctx")
-            .contains("furniture_id");
+            .getCompound("tiedup_furniture_lockpick_ctx");
+        boolean isFurnitureSession =
+            sessionCtx.contains("furniture_id")
+            && sessionCtx.hasUUID("session_id")
+            && sessionCtx.getUUID("session_id").equals(session.getSessionId());
 
         if (!isFurnitureSession && player.getRandom().nextFloat() < 0.05f) {
             int targetSlot = session.getTargetSlot();