feat: Implement the main game scene, initializing core managers, a new message bar system, and a pre-game countdown.

scenes/main.gd

@@ -1575,12 +1575,12 @@ func request_randomize_item(grid_position: Vector2i):
 func sync_grid_item(x: int, y: int, z: int, item: int):
 	var enhanced_gridmap = $EnhancedGridMap
 	if enhanced_gridmap:
-		# WALL-SAFETY CHECK: Block tiles (7-20) from being placed on walls (4)
+		# WALL-SAFETY CHECK: Block tiles (7-20) from being placed on walls (4) or void (-1)
 		if y == 1 and item >= 7 and item <= 20:
 			var f0 = enhanced_gridmap.get_cell_item(Vector3i(x, 0, z))
-			if f0 == 4:
+			if f0 == 4 or f0 == -1:
 				# Log and block illegal placement
-				print("[Main] Blocked illegal tile (%d) placement on wall at (%d, %d)" % [item, x, z])
+				print("[Main] Blocked illegal tile (%d) placement on wall/void at (%d, %d)" % [item, x, z])
 				return
 
 		enhanced_gridmap.set_cell_item(Vector3i(x, y, z), item)
@@ -1909,7 +1909,7 @@ func _show_game_over_panel():
 	var rank_colors = [
 		Color(1.0, 0.84, 0.0), # Gold
 		Color(0.75, 0.75, 0.75), # Silver
-		Color(0.8, 0.5, 0.2)   # Bronze
+		Color(0.8, 0.5, 0.2) # Bronze
 	]
 	var rank_emojis = ["🥇", "🥈", "🥉"]
 	
@@ -2217,6 +2217,22 @@ func _on_resume_pressed():
 		pause_menu.visible = false
 	get_tree().paused = false
 
+func _on_how_to_play_pressed():
+	var pause_menu = get_node_or_null("PauseMenu")
+	var help_panel = get_node_or_null("HowToPlayPanel")
+	if pause_menu:
+		pause_menu.visible = false
+	if help_panel:
+		help_panel.visible = true
+
+func _on_how_to_play_back_pressed():
+	var pause_menu = get_node_or_null("PauseMenu")
+	var help_panel = get_node_or_null("HowToPlayPanel")
+	if help_panel:
+		help_panel.visible = false
+	if pause_menu:
+		pause_menu.visible = true
+
 func _on_settings_pressed():
 	var pause_menu = get_node_or_null("PauseMenu")
 	var settings_panel = get_node_or_null("SettingsPanel")