Tooling and app should compile and run when no components are found

## Background
The tooling was created in Toolkit Labs, and was created using CanvasLayout as our testing ground. The tooling has only ever been used with at _least_ one component present.

## Problem
The tooling fails in some places when no components are found. This manifests in various forms.

## Solution
This issue documents and tracks the various problems we've found when no components are present. See comments below.

まず、コンポーネントが存在しない状態で tooling とアプリを再現し、その後、文書化されている失敗箇所について issue のコメントを確認します。コンポーネントが見つからない場合でも、tooling とアプリの両方が正常にコンパイルおよび実行できれば完了です。

索引モデルが issue の本文から書いたものです。