feat(poc): implement Sprint 1 proof of concept

- project.godot with autoload configuration
- Reception room with placeholder visuals
- Draggable Character with DragDropComponent
- Interactive flower object with bounce animation
- GameState, SaveManager, AudioManager, InputManager autoloads
- HUD with back button and music toggle

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

scripts/systems/drag_drop_component.gd

@@ -0,0 +1,80 @@
+## DragDropComponent — reusable drag-and-drop node; attach to any Character or InteractiveObject.
+class_name DragDropComponent extends Node
+
+signal drag_picked_up(global_position: Vector2)
+signal drag_released(global_position: Vector2)
+
+const DRAG_Z_INDEX: int = 10
+const DRAG_SCALE: float = 1.1
+
+@export var drag_target: Node2D
+
+var _is_dragging: bool = false
+var _drag_offset: Vector2 = Vector2.ZERO
+var _original_z_index: int = 0
+var _original_scale: Vector2 = Vector2.ONE
+
+
+func _ready() -> void:
+	if drag_target == null:
+		drag_target = get_parent() as Node2D
+
+
+func _input(event: InputEvent) -> void:
+	if event is InputEventScreenTouch:
+		_handle_press(event.pressed, event.position)
+	elif event is InputEventScreenDrag and _is_dragging:
+		_move_to(event.position)
+	elif event is InputEventMouseButton and event.button_index == MOUSE_BUTTON_LEFT:
+		_handle_press(event.pressed, event.position)
+	elif event is InputEventMouseMotion and _is_dragging:
+		_move_to(event.position)
+
+
+func _handle_press(pressed: bool, screen_pos: Vector2) -> void:
+	if pressed and _is_position_over_target(screen_pos):
+		_start_drag(screen_pos)
+	elif not pressed and _is_dragging:
+		_end_drag(screen_pos)
+
+
+func _start_drag(screen_pos: Vector2) -> void:
+	_is_dragging = true
+	var world_pos: Vector2 = _screen_to_world(screen_pos)
+	_drag_offset = drag_target.global_position - world_pos
+	_original_z_index = drag_target.z_index
+	_original_scale = drag_target.scale
+	drag_target.z_index = DRAG_Z_INDEX
+	drag_target.scale = _original_scale * DRAG_SCALE
+	drag_picked_up.emit(drag_target.global_position)
+
+
+func _end_drag(_screen_pos: Vector2) -> void:
+	_is_dragging = false
+	drag_target.z_index = _original_z_index
+	drag_target.scale = _original_scale
+	drag_released.emit(drag_target.global_position)
+
+
+func _move_to(screen_pos: Vector2) -> void:
+	var world_pos: Vector2 = _screen_to_world(screen_pos)
+	drag_target.global_position = world_pos + _drag_offset
+
+
+func _screen_to_world(screen_pos: Vector2) -> Vector2:
+	var canvas_transform: Transform2D = drag_target.get_viewport().get_canvas_transform()
+	return canvas_transform.affine_inverse() * screen_pos
+
+
+func _is_position_over_target(screen_pos: Vector2) -> bool:
+	if drag_target == null:
+		return false
+	var world_pos: Vector2 = _screen_to_world(screen_pos)
+	var local_pos: Vector2 = drag_target.to_local(world_pos)
+	var area: Area2D = drag_target.get_node_or_null("CollisionArea") as Area2D
+	if area == null:
+		return local_pos.length() < 64.0
+	for child in area.get_children():
+		if child is CollisionShape2D and child.shape != null:
+			return child.shape.get_rect().has_point(local_pos)
+	return local_pos.length() < 64.0

scripts/systems/hud.gd

@@ -0,0 +1,21 @@
+## HUD — heads-up display with back button and music toggle.
+extends CanvasLayer
+
+var _music_enabled: bool = true
+
+
+func _ready() -> void:
+	pass
+
+
+func _on_back_button_pressed() -> void:
+	get_tree().quit()
+
+
+func _on_music_toggle_pressed() -> void:
+	_music_enabled = not _music_enabled
+	var volume: float = AudioManager.DEFAULT_MUSIC_VOLUME if _music_enabled else 0.0
+	AudioManager.set_music_volume(volume)
+	var btn: Button = get_node_or_null("MusicToggle") as Button
+	if btn != null:
+		btn.text = "♪" if _music_enabled else "✕"