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/autoload/GameState.gd

@@ -0,0 +1,45 @@
+## GameState — global game state: character positions, object states, current room.
+extends Node
+
+signal state_changed
+signal character_moved(character_id: String, position: Vector2)
+
+var _character_positions: Dictionary = {}
+var _object_states: Dictionary = {}
+var current_room: String = "reception"
+
+
+func get_character_position(id: String) -> Vector2:
+	return _character_positions.get(id, Vector2.ZERO)
+
+
+func set_character_position(id: String, pos: Vector2) -> void:
+	_character_positions[id] = pos
+	character_moved.emit(id, pos)
+	state_changed.emit()
+
+
+func get_object_state(id: String) -> String:
+	return _object_states.get(id, "idle")
+
+
+func set_object_state(id: String, state: String) -> void:
+	_object_states[id] = state
+	state_changed.emit()
+
+
+func get_save_data() -> Dictionary:
+	return {
+		"character_positions": _character_positions,
+		"object_states": _object_states,
+		"current_room": current_room,
+	}
+
+
+func apply_save_data(data: Dictionary) -> void:
+	if data.has("character_positions"):
+		_character_positions = data["character_positions"]
+	if data.has("object_states"):
+		_object_states = data["object_states"]
+	if data.has("current_room"):
+		current_room = data["current_room"]