Consider moving event handling to mjolnir.js (vis.gl)? #191

Cosmos currently uses d3-zoom and d3-drag for pan/zoom and point drag, plus D3/DOM for click, hover, and keyboard.

One option is to switch to the vis.gl event manager, mjolnir.js. Deck.gl’s view controllers already use mjolnir.js, so this would align cosmos with the same event stack (luma.gl + mjolnir) and could simplify integration if cosmos and deck are used together.