Add proxy actor safety test and doc update

Introduce a game-thread-only ProxyActorController that resolves and moves a placed proxy actor in a test cell for initial visual-control validation. Adds include/F4TProxyActorController.h and plugin/src/F4TProxyActorController.cpp which implement editor ID, base-actor, and fallback-form lookup paths, handle caching, throttled logging, movement throttling, and a simple player-offset teleport. Hooked UpdateSafetyTest into the existing periodic game-thread task in main.cpp. Updated docs/dev-log.md with the 2026-05-31 entry describing the test results and next steps. This is a temporary safety test (uses local player offset) intended to be replaced by real remote-player syncing later.

docs/dev-log.md

@@ -572,3 +572,38 @@ Use this format for future updates:
 - ...
 ```
 
+## 2026-05-31
+
+### What Changed
+
+- Fixed proxy actor lookup for `F4TProxyRemotePlayer01REF`.
+- Added more robust lookup logic for the placed proxy actor.
+- Confirmed the plugin can control a placed actor reference in `F4TTestCell01`.
+- The proxy actor now moves to the local player position plus an offset.
+
+### What Worked
+
+- Fallout 4 launched through F4SE.
+- `coc F4TTestCell01` worked.
+- The proxy actor was found successfully.
+- The proxy actor teleported to the player position plus offset.
+- Actor movement occurred from the safe game-thread update path.
+- The networking receive thread still does not touch Fallout 4 actors.
+
+### What Broke
+
+- Nothing recorded.
+
+### Notes
+
+- This is the first successful visible actor-control test for Fallout 4 Together.
+- The proxy is still driven by local player position plus offset, not remote player state.
+- Dynamic spawning is still not implemented.
+- Remote actor syncing has not started yet.
+
+### Next Steps
+
+- Replace local-player-offset movement with remote player state movement.
+- Only move the proxy when the remote player is in the same cell/worldspace.
+- Snap movement first.
+- Add smoothing/interpolation later.