Add plugin receive loop & remote player state

Add a networking receive loop and in-plugin remote-player storage. Introduces F4TRemotePlayerState (header + implementation) to track assigned playerId and remote player snapshots with thread-safe access. Expands F4TNetworking to start/stop a background receive thread, parse newline-separated JSON packets (welcome, transform, disconnect), validate fields, update remote state, throttle logs, and handle socket/thread synchronization. Add nlohmann_json to xmake and plugin build. Update docs and dev log to reflect the new receive behavior and current prototype scope.

protocol/message-types.md

@@ -20,12 +20,13 @@ Current behavior:
   broadcast to other connected clients.
 - `disconnect` is sent by the server when a client disconnects.
 
-The Fallout 4 plugin currently sends transform packets only. It does not yet
-receive or process server packets.
+The Fallout 4 plugin sends transform packets and receives `welcome`,
+`transform`, and `disconnect` packets. Received transforms are stored as plain
+remote-player state only.
 
-## Working In Fake Client Only
+## Current Receivers
 
-`server/fake_client.py` currently receives:
+The Fallout 4 plugin and `server/fake_client.py` currently receive:
 
 ```text
 welcome
@@ -33,8 +34,8 @@ transform
 disconnect
 ```
 
-The fake client stores broadcast transform packets in an in-memory remote player
-state table and removes entries when disconnect packets arrive.
+The plugin and fake client store broadcast transform packets in in-memory remote
+player state tables and remove entries when disconnect packets arrive.
 
 ## Planned Later
 

protocol/packets.md

@@ -40,8 +40,8 @@ playerId    Server-assigned player ID for this connection.
 serverTime  Server timestamp when the welcome packet was created.
 ```
 
-The Fallout 4 plugin does not yet read this packet. `server/fake_client.py`
-currently receives and prints it.
+The Fallout 4 plugin and `server/fake_client.py` receive this packet. The plugin
+stores the assigned `playerId` for filtering its own future transform echoes.
 
 ### Transform Packet
 
@@ -117,20 +117,24 @@ playerId    Server-assigned player ID that disconnected.
 serverTime  Server timestamp when the disconnect packet was created.
 ```
 
-`server/fake_client.py` currently uses this packet to remove remote players from
-its in-memory state table.
+The Fallout 4 plugin and `server/fake_client.py` use this packet to remove
+remote players from their in-memory state tables.
 
-## Working In Fake Client Only
+## Receiver Behavior
 
-- Receiving `welcome` packets.
-- Receiving broadcast `transform` packets from other clients.
-- Storing remote player state by `playerId`.
-- Removing remote player state when `disconnect` packets arrive.
+The Fallout 4 plugin and fake client both receive:
+
+```text
+welcome
+transform
+disconnect
+```
+
+The plugin receive loop runs on a background networking thread. It stores plain
+remote-player state only and does not spawn actors or touch Fallout 4 game
+objects.
 
 ## Planned Later
 
-- Fallout 4 plugin receive loop.
-- Plugin-side parsing of `welcome`, `transform`, and `disconnect` packets.
-- Plugin-side remote player state storage.
 - Remote actor spawning.
 - Gameplay synchronization.

protocol/player-sync.md

@@ -6,23 +6,24 @@ The current implementation is still a local networking prototype.
 ## Current Implemented Flow
 
 ```text
-Fallout 4 Plugin
+Fallout 4 Plugin ↔ Local Python Server ↔ Other Clients
         ↓
-Local Python Server
-        ↓
-Fake Client Remote Player State
+Plugin Remote Player State
 ```
 
 The Fallout 4 plugin currently reads the local player's transform and sends it
 to the local Python server. The server assigns a `playerId`, adds `serverTime`,
 and broadcasts transform packets to other connected clients.
 
-The Fallout 4 plugin does not yet receive remote transforms from the server.
-The current receiver is `server/fake_client.py`.
+The Fallout 4 plugin also receives server packets on a background networking
+thread. It stores its assigned `playerId`, stores remote transform state by
+remote `playerId`, and removes remote state when disconnect packets arrive.
+`server/fake_client.py` remains a lightweight test receiver for the same packet
+lifecycle.
 
 ## Current Remote Player State Model
 
-The fake client stores remote players by `playerId`.
+The plugin and fake client store remote players by `playerId`.
 
 Each remote player state entry tracks:
 
@@ -40,13 +41,16 @@ serverTime
 lastReceivedLocalTime
 ```
 
-This model is a prototype for the eventual Fallout 4 receiving client. The goal
-is to prove the data shape and lifecycle before adding a plugin receive loop or
-spawning remote actors.
+This model proves the data shape and lifecycle before spawning remote actors.
 
 ## Implemented
 
 - The plugin sends local player transform packets.
+- The plugin receives `welcome` packets and stores its assigned `playerId`.
+- The plugin receives broadcast transform packets.
+- The plugin ignores transform packets for its own assigned `playerId`.
+- The plugin stores remote player state by `playerId`.
+- The plugin receives `disconnect` packets and removes remote player state.
 - The server assigns incrementing `playerId` values.
 - The server sends `welcome` packets.
 - The server adds `playerId` and `serverTime` to transform packets.
@@ -55,19 +59,10 @@ spawning remote actors.
 - The server broadcasts `disconnect` packets.
 - The fake client removes disconnected remote players from its state table.
 
-## Working In Fake Client Only
-
-- Receiving broadcast transform packets.
-- Tracking remote player state.
-- Handling disconnect cleanup.
-
 No Fallout 4 remote actor is spawned yet.
 
 ## Planned Later
 
-- Add a Fallout 4 plugin receive loop.
-- Parse `welcome`, `transform`, and `disconnect` packets in the plugin.
-- Store remote player state inside the plugin.
 - Add interpolation or smoothing after plugin-side state exists.
 - Spawn and move remote actors only after the receive loop is stable.