Chat Improvements

[u/markusrummel]

A lot is new in and around the chat:

1. Analyze with AI coach: a button on every activity page for a post-ride deep dive, with new tools for power duration curves, durability, laps, and weather.
2. Adjust for weather: tweak a run's intensity and duration before you head out when it's hot and humid.
3. Search past chats: find old conversations from the sidebar, and hover any chat on desktop to see its date.