Linked maps side by side

**Is your feature request related to a problem? Please describe.**
Using side by side maps that are in sync. Map #1 uses a small geoparquet file, the other Map #2 uses a very large geoparquet file. When the user interacts with Map #1 I want to use the map bounding-box/view-extent to query the data to update Map #2.

**Describe the solution you'd like**
Public function to get the bounding box of the Map. i.e. map.getBounds()
Event state change to Map's bounding box.

**Describe alternatives you've considered**
Tested access to compute_view (private fn, i.e. wont work) to access bbox from pydeck.ViewPort.

**Additional context**
Add any other context or screenshots about the feature request here.

Hoping to be pointed in the right direction for a friendly way to get bbox.

The issue names no files or tests. Start by tracing the public Map API and the private compute_view/pydeck.ViewPort path mentioned, then determine where map view state is exposed. Done means users can retrieve the Map bounding box and receive a state-change event suitable for updating a second map.

Written by the indexing model from the issue text.