Favorites and Guides: saved places and collections

Apple Maps lets you save places to Favorites and to Guides (named collections), shown on the map and in search's empty state. ts-maps search keeps Recents only (SearchHistory, in localStorage).

Scope

• A SavedPlaces store: favorites plus named collections, with a pluggable backend (localStorage by default, and an async interface for syncing to a server).
• A Save button on the place card, and saved places shown on the map with a distinct marker.
• Favorites shown in search's empty state above Recents, and Guides browsable from there.
• Import/export as GeoJSON.
• Bindings parity (events for save/unsave).