Implement proxy weapon animation sync for ranged guns

Milestone 1: Proxy actors now equip remote players' right-hand weapons and play armed idle/locomotion poses when weaponDrawn=true. Adds rightHand weapon slot to equippedItems protocol, weapon graph variable support (iSyncGunDown: 0=drawn, 1=holstered), and weapon FSM events (weaponDraw, readyStateEnter, gunDownStateEnter). Fixes two critical animation state churn bugs: frustum-visibility flicker no longer resets animation state on every update tick, and idle proxies no longer register as changed on every frame. Includes WeaponBehavior graph loading via AIProcess::RequestLoadAnimationsForWeaponChange() and manual weapon attachment fallback. New docs/weapon-animation-sync.md reference guide maps animation events and variables from F4-Animation-Research. Experimental alert-state reassertion for armed proxies to test NPC combat state gating of weapon-ready poses.

protocol/player-sync.md

@@ -127,8 +127,10 @@ player exists.
 - Transform packets include movement state data (`isMoving`, `movementSpeed`,
   `isSprinting`, `isSneaking`, `isJumping`, `weaponDrawn`).
 - Transform packets can include optional `equippedItems` snapshots for visible
-  clothing, armor, hats, and eyewear slots. The game-thread proxy controller
-  applies those snapshots after proxy 3D is loaded.
+  clothing, armor, hats, eyewear, and right-hand weapon slots. The game-thread
+  proxy controller applies those snapshots after proxy 3D is loaded. Weapons are
+  synced as optional `WEAP` form IDs; missing weapons or unresolved form IDs do
+  not block other equipment sync.
 - Transform packets can include optional `appearance` snapshots for best-effort
   body and face proxy visuals. The game-thread proxy controller applies supported
   fields after proxy 3D is loaded and defers race/gender switching.
@@ -136,7 +138,8 @@ player exists.
   `COVault109` solo cell.
 - The game-thread proxy controller applies confirmed Havok animation graph
   variables to runtime proxy actors from that remote state (locomotion, sneak,
-  jump, weapon drawn). Transform position/heading sync is unchanged.
+  jump). Weapon-drawn state is parsed but animation application is implemented
+  separately (Phase 2 milestone). Transform position/heading sync is unchanged.
 
 ## Transform Cadence