Add local animation graph read-only debug

Introduce a game-thread-only, read-only diagnostic helper to probe local player animation graph variables and (optionally) numeric cache IDs. Adds F4TLocalAnimationGraphDebug.h/cpp with UpdateLocalPlayerAnimationGraphDebug(...) and wires a call into plugin/src/main.cpp immediately after GetPlayerMovementState. The helper probes curated variable names via CommonLibF4 read-only APIs, logs availability/changes, and includes a disabled-by-default numeric cache ID scan (kEnableLocalPlayerAnimationGraphCacheIdReadOnlyDebug = false) due to a reported crash during testing. Update also adds extensive dev-log documentation (docs/dev-log.md) describing behavior, testing notes, and rollback instructions. Build succeeded; manual F4SE in-game verification remains pending.

plugin/include/F4TLocalAnimationGraphDebug.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <chrono>
+
+namespace RE
+{
+	class PlayerCharacter;
+}
+
+namespace F4T::LocalAnimationGraphDebug
+{
+	// Game-thread-only, read-only diagnostics for discovering local player
+	// animation graph variables before any proxy visual animation writes.
+	void UpdateLocalPlayerAnimationGraphDebug(
+		RE::PlayerCharacter& a_player,
+		bool a_isMoving,
+		bool a_isSprinting,
+		bool a_isSneaking,
+		bool a_isJumping,
+		bool a_weaponDrawn,
+		float a_movementSpeed,
+		std::chrono::steady_clock::time_point a_currentTime);
+}