Add bidirectional location sharing between contacts:
- LocationSharingManager handles outgoing sharing sessions
- LocationTelemetry model with cease flag for stop notifications
- ReceivedLocationDao/Entity for storing incoming locations
- ContactLocationBottomSheet for viewing contact details on map
- MapViewModel combines contacts + announces for display names
- Python wrapper filters location-only messages from chat view
When a user stops sharing, a cease message is sent to recipients
causing immediate marker removal instead of waiting for expiry.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>