feat: Implement UIManager for player action, playerboard, and power-up UI, and add initial lobby, main scenes, and PlayerboardManager.

scripts/managers/playerboard_manager.gd

@@ -10,6 +10,12 @@ var selected_gridmap_position = Vector2i(-1, -1)
 var selected_playerboard_slot = -1
 var targeted_playerboard_slot = -1
 
+# 0-based indices corresponding to User's 1-based request: 1,5,6,10,11,15,16,20,21,22,23,24,25
+const HIDDEN_SLOTS = [0, 4, 5, 9, 10, 14, 15, 19, 20, 21, 22, 23, 24]
+
+func is_valid_playerboard_slot(slot_index: int) -> bool:
+	return not (slot_index in HIDDEN_SLOTS)
+
 func initialize(p_player: Node3D, p_gridmap: Node):
 	player = p_player
 	enhanced_gridmap = p_gridmap
@@ -253,7 +259,13 @@ func bot_try_grab_item() -> bool:
 	var item = enhanced_gridmap.get_cell_item(current_cell)
 	
 	if item != -1:
-		var empty_slot = player.playerboard.find(-1)
+		# Find empty slot that is NOT hidden
+		var empty_slot = -1
+		for i in range(player.playerboard.size()):
+			if player.playerboard[i] == -1 and not (i in HIDDEN_SLOTS):
+				empty_slot = i
+				break
+				
 		if empty_slot != -1:
 			if player.is_multiplayer_authority():
 				# Convert Holo (11-14)
@@ -281,7 +293,13 @@ func bot_try_grab_item() -> bool:
 			var cell = Vector3i(neighbor.position.x, 1, neighbor.position.y)
 			item = enhanced_gridmap.get_cell_item(cell)
 			if item != -1:
-				var empty_slot = player.playerboard.find(-1)
+				# Find empty slot that is NOT hidden
+				var empty_slot = -1
+				for i in range(player.playerboard.size()):
+					if player.playerboard[i] == -1 and not (i in HIDDEN_SLOTS):
+						empty_slot = i
+						break
+						
 				if empty_slot != -1:
 					if player.is_multiplayer_authority():
 						player.playerboard[empty_slot] = item
@@ -477,7 +495,7 @@ func handle_slot_clicked(slot_index: int):
 		return
 
 	var adjacent_slots = get_adjacent_playerboard_slots(selected_playerboard_slot)
-	if slot_index in adjacent_slots and player.playerboard[slot_index] == -1:
+	if slot_index in adjacent_slots and player.playerboard[slot_index] == -1 and not (slot_index in HIDDEN_SLOTS):
 		# Move item to empty target slot
 		var selected_item = player.playerboard[selected_playerboard_slot]
 		player.playerboard[slot_index] = selected_item
@@ -526,11 +544,26 @@ func find_best_goal_slot_for_item(item: int) -> int:
 				var board_row = i + 1 # offset to center in 5x5
 				var board_col = j + 1
 				var slot_index = board_row * 5 + board_col
+				
+				# Ensure this slot is not hidden (though 3x3 center should be safe, best to check)
+				if slot_index in HIDDEN_SLOTS:
+					continue
+					
 				if player.playerboard[slot_index] == -1: # only if empty
 					return slot_index
 
-	# No ideal slot? Return any empty slot
-	return player.playerboard.find(-1)
+	# No ideal goal slot? Look for any empty slot that is NOT hidden AND NOT reserved for Goals
+	# Goal slots are row 2-3, col 1-3 (indices: 11,12,13, 16,17,18) matching User request
+	# Rows 1 (6,7,8) are now storage slots
+	var reserved_goal_slots = [11, 12, 13, 16, 17, 18]
+	
+	for i in range(player.playerboard.size()):
+		if player.playerboard[i] == -1:
+			if i in HIDDEN_SLOTS: continue
+			if i in reserved_goal_slots: continue # Skip if it's a goal slot (reserved)
+			return i
+			
+	return -1
 
 func find_best_put_candidate() -> Dictionary:
 	# Convert goals to 2D (3x3)
@@ -651,7 +684,11 @@ func has_items_in_playerboard() -> bool:
 	return player.playerboard.any(func(item): return item != -1)
 
 func playerboard_is_full() -> bool:
-	return player.playerboard.find(-1) == -1
+	# Check if any NON-HIDDEN slot is empty
+	for i in range(player.playerboard.size()):
+		if not (i in HIDDEN_SLOTS) and player.playerboard[i] == -1:
+			return false
+	return true
 
 # Slot selection management
 func select_playerboard_slot(slot_index: int):