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.

plugin/include/F4TProxyActorController.h

@@ -0,0 +1,8 @@
+#pragma once
+
+namespace F4T::ProxyActorController
+{
+	// Temporary game-thread-only actor-control safety test. This validates that the
+	// plugin can resolve and move the placed proxy before remote-player visual sync.
+	void UpdateSafetyTest();
+}