feat(integration): Main scene wires world+dolphin+ambience with signal routing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/Main.gd

@@ -0,0 +1,42 @@
+extends Node3D
+
+@onready var world: Node3D = $World/ChunkManager
+@onready var dolphin: CharacterBody3D = $Dolphin
+@onready var hud: CanvasLayer = $Dolphin/HUD
+@onready var plankton_follower: Node3D = $PlanktonFollower
+
+
+func _ready() -> void:
+	dolphin.block_break_requested.connect(_on_block_break)
+	dolphin.block_place_requested.connect(_on_block_place)
+	dolphin.echolocation_triggered.connect(_on_echolocation)
+
+	if is_instance_valid(hud) and hud.has_method("connect_to_dolphin"):
+		hud.connect_to_dolphin(dolphin)
+
+	AudioManager.play_ambient_loop("underwater_ambient")
+	AudioManager.play_music("underwater_theme")
+	AudioManager.play_whale_call_random()
+
+	world.world_seed = 12345
+
+
+func _process(_delta: float) -> void:
+	world.update_player_position(dolphin.global_position)
+	plankton_follower.global_position = dolphin.global_position
+
+
+func _on_block_break(hit_position: Vector3, _normal: Vector3) -> void:
+	var broken_id := world.break_block(hit_position)
+	if broken_id > 0:
+		AudioManager.play_bubble_sfx(hit_position)
+
+
+func _on_block_place(hit_position: Vector3, normal: Vector3) -> void:
+	var place_pos := hit_position + normal * 0.5
+	var current_selected_block := 2
+	world.place_block(place_pos, current_selected_block)
+
+
+func _on_echolocation(position: Vector3, _radius: float) -> void:
+	AudioManager.play_bubble_sfx(position)