feat: implement global SFXManager singleton and integrate into main scene initialization

scenes/player.gd

@@ -76,6 +76,8 @@ var is_attack_mode: bool = false:
 			return # Prevent infinite recursion / redundant updates
 			
 		is_attack_mode = value
+		if is_attack_mode:
+			attack_mode_timer = MAX_ATTACK_MODE_TIME
 		_refresh_player_visuals()
 			
 		# Sync to others if we are the authority
@@ -836,6 +838,8 @@ var slow_timer: float = 0.0
 var tekton_carry_timer: float = 0.0
 const MAX_TEKTON_CARRY_TIME: float = 3.0
 
+var attack_mode_timer: float = 0.0
+const MAX_ATTACK_MODE_TIME: float = 5.0
 
 @rpc("any_peer", "call_local")
 func apply_stagger(duration: float = 1.5):
@@ -1184,12 +1188,24 @@ func _process(delta):
 	if movement_manager:
 		movement_manager._process(delta)
 
+	# Attack/Knock Mode Expiration Timer
+	if is_multiplayer_authority() and (is_attack_mode or is_knock_mode):
+		if attack_mode_timer > 0:
+			attack_mode_timer -= delta
+			if attack_mode_timer <= 0:
+				attack_mode_timer = 0.0
+				is_attack_mode = false
+				is_knock_mode = false
+				NotificationManager.send_message(self, "Knock Mode Expired!", NotificationManager.MessageType.WARNING)
+				if powerup_manager:
+					powerup_manager.reset_boost()
+
 	# Immunity Timer Logic
 	if immunity_timer > 0:
 		immunity_timer -= delta
 		if immunity_timer <= 0:
 			immunity_timer = 0
-			_apply_tint_recursive(self , Color.WHITE) # Remove immunity tint
+			_apply_tint_recursive(self, Color.WHITE) # Remove immunity tint
 			
 	# Slow Timer Logic
 	if slow_timer > 0:
@@ -2445,6 +2461,8 @@ var is_knock_mode: bool = false:
 	set(value):
 		if is_knock_mode == value: return
 		is_knock_mode = value
+		if is_knock_mode:
+			attack_mode_timer = MAX_ATTACK_MODE_TIME
 		_refresh_player_visuals()
 
 func enter_attack_mode():