Add COVault109 solo-cell handling

Implement solo-cell logic to suppress transform packet sends and remote proxy representation while the local player is in COVault109, allowing first-time character creation to remain visually single-player. One entry location update is sent so other clients can hold stale proxies before suppression begins. Added F4TSoloCell.h helper for load-order-independent solo cell recognition by editor ID and cached FormID.

plugin/include/F4TSoloCell.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <string_view>
+
+namespace F4T::SoloCell
+{
+	inline constexpr auto kVault109EditorId = "COVault109";
+
+	inline std::optional<std::uint32_t>& GetVault109CellIdCache()
+	{
+		static std::optional<std::uint32_t> s_vault109CellId;
+		return s_vault109CellId;
+	}
+
+	inline bool HasEditorId(const RE::TESObjectCELL& a_cell, std::string_view a_editorId)
+	{
+		const auto* cellEditorId = a_cell.GetFormEditorID();
+		return cellEditorId && a_editorId == cellEditorId;
+	}
+
+	inline bool IsSoloCell(const RE::TESObjectCELL& a_cell)
+	{
+		if (HasEditorId(a_cell, kVault109EditorId)) {
+			return true;
+		}
+
+		auto& vault109CellId = GetVault109CellIdCache();
+		if (!vault109CellId) {
+			const auto* vault109Cell = RE::TESForm::GetFormByEditorID<RE::TESObjectCELL>(
+				RE::BSFixedString{ kVault109EditorId });
+			if (vault109Cell) {
+				vault109CellId = vault109Cell->GetFormID();
+			}
+		}
+
+		return vault109CellId && a_cell.GetFormID() == *vault109CellId;
+	}
+}

plugin/src/F4TProxyActorController.cpp

@@ -9,6 +9,7 @@
 #include "F4RemoteActionComponent.h"
 #include "F4TInterpolationSystem.h"
 #include "F4TProxyGameAPI.h"
+#include "F4TSoloCell.h"
 
 #include "RE/A/ACTOR_STANCE.h"
 #include "RE/A/ActorValue.h"
@@ -1700,6 +1701,13 @@ namespace
 		const RE::PlayerCharacter& a_player,
 		const RE::TESObjectCELL& a_parentCell)
 	{
+		if (F4T::SoloCell::IsSoloCell(a_parentCell)) {
+			LogThrottledInfo(
+				"solo_cell_proxy_suppressed",
+				"COVault109 is a solo cell; remote proxy representation is suppressed while local player is inside.");
+			return false;
+		}
+
 		const auto remoteCellId = ParseHexFormId(a_remotePlayer.cellId);
 		if (!remoteCellId) {
 			LogThrottledWarning(

plugin/src/main.cpp

@@ -6,6 +6,7 @@
 #include "F4TProxyActorController.h"
 #include "F4TProxyAnimationSync.h"
 #include "F4TProxyPuppet.h"
+#include "F4TSoloCell.h"
 #include "F4TWorldStateSync.h"
 
 #include "RE/A/ACTOR_STANCE.h"
@@ -34,6 +35,7 @@ namespace
 		std::uint32_t cellId;
 		bool hasWorldspaceId;
 		std::uint32_t worldspaceId;
+		bool isSoloCell;
 	};
 
 	struct PlayerMovementState
@@ -133,13 +135,15 @@ namespace
 			false,
 			0,
 			false,
-			0
+			0,
+			false
 		};
 
 		const auto* parentCell = a_player.GetParentCell();
 		if (parentCell) {
 			location.hasCellId = true;
 			location.cellId = parentCell->GetFormID();
+			location.isSoloCell = F4T::SoloCell::IsSoloCell(*parentCell);
 		}
 
 		if (a_player.cachedWorldspace) {
@@ -480,6 +484,7 @@ namespace
 		static auto lastDebugSampleTime = std::chrono::steady_clock::time_point{};
 		static auto debugMovingHoldUntil = std::chrono::steady_clock::time_point{};
 		static auto networkMovingHoldUntil = std::chrono::steady_clock::time_point{};
+		static bool soloCellTransformSuppressed = false;
 
 		const auto currentTransform = GetPlayerTransform(*player);
 		const auto currentLocation = GetPlayerLocation(*player);
@@ -501,6 +506,29 @@ namespace
 			debugMovementState.weaponDrawn,
 			debugMovementState.movementSpeed,
 			currentTime);
+
+		if (currentLocation.isSoloCell && soloCellTransformSuppressed) {
+			lastSentTransform = currentTransform;
+			lastDebugSampleTransform = currentTransform;
+			lastKnownLocation = currentLocation;
+			lastSentMovementState = debugMovementState;
+			lastSendTime = currentTime;
+			lastLogTime = currentTime;
+			lastDebugSampleTime = currentTime;
+			hasLastTransform = true;
+
+			return;
+		}
+
+		if (currentLocation.isSoloCell) {
+			LogInfoWithLocalPlayerPrefix("COVault109 is a solo cell; sending entry location update before suppressing further transforms.");
+		}
+
+		if (soloCellTransformSuppressed) {
+			LogInfoWithLocalPlayerPrefix("Local player left solo cell; transform packet sending resumed.");
+			soloCellTransformSuppressed = false;
+		}
+
 		if (!hasLastTransform) {
 			lastSentTransform = currentTransform;
 			lastDebugSampleTransform = currentTransform;
@@ -538,6 +566,9 @@ namespace
 						std::format(", worldspaceId={:08X}", currentLocation.worldspaceId) :
 						std::string{}));
 			}
+			if (currentLocation.isSoloCell) {
+				soloCellTransformSuppressed = true;
+			}
 			return;
 		}
 
@@ -627,6 +658,11 @@ namespace
 				LogPlayerTransform(currentTransform);
 				lastLogTime = currentTime;
 			}
+
+		}
+
+		if (currentLocation.isSoloCell) {
+			soloCellTransformSuppressed = true;
 		}
 
 		lastDebugSampleTransform = currentTransform;