Small Fixes and Improvements

A few smaller changes that shipped this week:

• The Ad library header now spans the full width of the page, with the Ad feed and Tracked companies rail sitting underneath it instead of beside it.
• Onboarding questions and the setup status messages got clearer wording, and competitors you add show a "fetching details" state until their ads arrive.
• The "Thinking..." label in chat no longer jumps when the reply starts streaming.