Highlight positive impacts in impact mode

This issue is a bit of a placeholder, but I wanted to capture some values expressed in todays discussion

While discussing if we should pursue #127 (outcome: probably not pursue in the immediate), we talked more generally about how it's important to highlight the positive impacts on walking and cycling.

There's value in emphasizing relativistic value rather than explicit hypothetical numbers.

e.g. rather than implying "This exact route will now be taken for this hypothetical trip", it could be more useful to say "this segment should see reduced traffic, making it a likely candidate for someones low stress commute"

Ultimately this might just be some additional copy and some UI affordances over the existing data in ["impact mode"](#36) .

Another suggestion: Juxtapose a route from A -> B along with the improved street segments (like shown in "impact mode") to emphasize how much of the streets along this route are improved. e.g. Useful for "safe route to school" planning.

既存の「impact mode」UI (#36)を確認し、現在、道路セグメントと改善内容がどのように表示されているかを理解してください。この作業では、交通量の削減や安全な経路計画など、プラスの影響を強調するための新しい文言とUI要素を追加します。テキストのレンダリングと地図の可視化を担うコンポーネントのコードを確認し、どこに変更が必要かを把握してください。目的は、仮定上の数値ではなく相対的なメリットを強調するよう、メッセージングを改善することです。

索引モデルが issue の本文から書いたものです。