feat: Implement powerup inventory UI and manager, introducing ghost and area freeze special tiles.

scenes/player.gd

@@ -613,11 +613,20 @@ func _apply_tint_recursive(node: Node, color: Color):
 		# If color is WHITE (reset), clear the overlay
 		if color == Color.WHITE:
 			node.material_overlay = null
+			node.transparency = 0.0 # Reset
 		else:
 			# If color is Blue (frozen), make it semi-transparent overlay
 			mat.albedo_color = color
-			mat.albedo_color.a = 0.5 # Semi-transparent
-			mat.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
+			
+			# Special Ghost Effect (Invisible Mode)
+			if color.a < 1.0:
+				mat.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
+				node.transparency = 0.5 # Make base mesh transparent too if possible, depending on material
+			else:
+				# Frozen
+				mat.albedo_color.a = 0.5 # Semi-transparent overlay
+				mat.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
+				
 			node.material_overlay = mat
 			
 	for child in node.get_children():
@@ -658,6 +667,37 @@ func apply_stagger(duration: float = 1.5):
 	else:
 		_apply_tint_recursive(self, Color.WHITE) # Remove tint
 
+@rpc("any_peer", "call_local")
+func apply_slow_effect(duration: float = 3.0):
+	# "area with blue like wall... Player who cross on that area will got slowed and freeze effect"
+	# Visual: Blue Tint
+	_apply_tint_recursive(self, Color(0.6, 0.8, 1.0)) # Icy Blue
+	
+	# Logic: Slow Movement speed
+	if movement_manager:
+		# Use 0.2 multipliers to match "slowed" request (20% speed)
+		movement_manager.set_speed_multiplier(0.2) 
+	
+	print("Player %s is slowed for %.1f seconds" % [name, duration])
+		
+	# Restore after duration
+	# Note: If they stand in the zone, this will be re-applied constantly, resetting the visual
+	await get_tree().create_timer(duration).timeout
+	
+	# Only restore if not re-applied recently (simple check: if still tinted?) 
+	# A better way is managing a "slow_timer" but for now let's just reset if timer expires.
+	# The persistent zone logic reapplies every frame, so we want this timer to be short 
+	# OR we rely on the zone logic. 
+	# The RPC call says "apply_slow_effect(0.5)", so it expires quickly.
+	
+	if movement_manager:
+		movement_manager.set_speed_multiplier(1.0)
+	
+	if immunity_timer > 0:
+		_apply_tint_recursive(self, Color(0.5, 1.0, 0.5))
+	else:
+		_apply_tint_recursive(self, Color.WHITE)
+
 func playerboard_is_empty() -> bool:
 	for item in playerboard:
 		if item != -1: