live data wiring

Today was about stitching everything together. The empty main.js is now a proper startup sequence: scene setup, globe layers, HUD, picking interactions, intro camera dolly, and the render loop - all hooked up in order. The fetch pipelines for earthquakes, ISS, aurora, and air quality are in, each with its own interval and sample fallback so the globe never loads blank. The intro camera dolly in from a bit further out still needs a tiny easing tweak, but it works