docs: proxy animation investigation conclusive - animations not feasible

Investigation summary:
- Tested velocity-based animation triggering: graph variable writes, animation
  events, character controller velocity manipulation, and Move() API calls
- All approaches failed: animations do not play on SetPosition-backed proxy actors
- Root cause: Fallout 4's animation system requires active AIProcess-driven
  locomotion packages, which are incompatible with networked puppet actors
- Fallout 4's animation system fundamentally ties animation evaluation to the
  character controller's actual velocity AND active AI-driven locomotion state
- PlaceAtMe proxies updated via SetPosition cannot provide either requirement

Proxy actors currently work correctly for:
- Smooth position synchronization
- Heading/rotation updates
- Jump animations (via Z-position)
- Network sync and lifecycle

What remains impossible without deep engine access:
- Walk/run/sneak animation playback
- Animation graph variable manipulation affecting behavior
- Character controller velocity synthesis for puppets

Recommendation: Accept this architectural limitation and provide alternative
visual feedback (particles, glows, state indicators) instead of animations.

Files changed:
- plugin/src/F4TProxyActorController.cpp: Reverted to SetPosition-only approach
- docs/dev-log.md: Added comprehensive investigation summary and conclusions

Co-authored-by: Cursor <cursoragent@cursor.com>

plugin/include/F4TProxyAnimationSync.h

@@ -0,0 +1,51 @@
+#pragma once
+
+#include "F4TRemotePlayerState.h"
+
+#include <cstdint>
+#include <optional>
+#include <string_view>
+
+namespace RE
+{
+	class Actor;
+}
+
+namespace F4T::ProxyAnimationSync
+{
+	// Confirmed via local read-by-name graph debug (Fallout4Together.log):
+	// - float "Speed" reads/writes while in-game (walk ~47-105)
+	// - bool "IsSprinting" reads while in-game
+	// - bIsMoving, bIsSneaking, bSprint, bInJumpState, bWeaponDrawn, Direction: unavailable by name
+	namespace GraphVar
+	{
+		inline constexpr const char* kSpeed = "Speed";
+		inline constexpr const char* kSpeedLower = "speed";
+		inline constexpr const char* kIsSprinting = "IsSprinting";
+	}
+
+	struct ProxyAppliedAnimationState
+	{
+		bool hasAppliedGraphState{ false };
+		bool lastIsMoving{ false };
+		bool lastIsSprinting{ false };
+		bool lastIsSneaking{ false };
+		bool lastIsJumping{ false };
+		bool lastWeaponDrawn{ false };
+		float lastGraphSpeed{ 0.0F };
+		float lastDirection{ 0.0F };
+	};
+
+	void ResetAppliedAnimationState(ProxyAppliedAnimationState& a_state);
+
+	void ApplyProxyAnimationFromRemoteState(
+		ProxyAppliedAnimationState& a_state,
+		RE::Actor& a_proxy,
+		const RemotePlayerState::RemotePlayerState& a_remotePlayer);
+
+	void ClearProxyAnimationState(
+		ProxyAppliedAnimationState& a_state,
+		RE::Actor& a_proxy,
+		std::uint32_t a_remotePlayerId,
+		std::string_view a_reason);
+}