Desktop App: Announce Focus Mode Changes & Proactive Tips

When a Focus Mode changes on your iPhone or Mac (Work, Sleep, DND, etc.), the Omi desktop app should speak a short contextual message out loud.

Examples:

- Work Focus turns on → "Work mode on. You have 3 meetings today, first one in 40 minutes."

- Sleep Focus turns on → "Winding down. Tomorrow's first event is at 9 AM."

- DND turns off → "You're back. You missed 2 calls and 5 messages."

On top of that, Omi could give proactive tips based on what it knows:

- "You've been in a meeting for 2 hours straight — maybe take a break?"

- "Your next meeting starts in 5 minutes, it's in a different building."

- "You haven't moved in 3 hours."

This would turn the desktop app into an ambient assistant that reacts to your device state, not just passively records. The desktop app already runs in the background — it just needs to listen to Focus Mode changes (available via macOS APIs) and optionally pull calendar data for context.