- Add relative timestamp display below each message bubble
- Show time only (HH:mm) for today's messages
- Show day + time (EEE HH:mm) for messages within 7 days
- Show date + time (d MMM HH:mm) for older messages
- Subtle styling: small font, reduced opacity
- Implemented for both Android (Compose) and iOS/macOS (SwiftUI)
When the user sends a message while reading older messages, scroll to
bottom so they can see their sent message and the response.
Fixes#2470
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
