- New StormLayer renders purple cloud clusters with a seeded charge → strike → afterglow envelope in the upper sky, using sprite compositing (back/flash/front trios) rather than shaders
- Add `stormEnvelope` + `sstep01` to SystemEffectsMath.js; refactor NebulaAtmosphere's cloud shape into a shared `cloudAlpha` used by both `drawCloud` and the storm's flash texture
- Extend EmberField with optional per-spark twinkle (rate/depth) so habitable fireflies pulse while redDwarf embers stay steady
- Wire StormLayer create/update/destroy into GameScene alongside the other content effects
- Populate `types.habitable.effect` in systems.json with grade, void, particles, and storm blocks; update landing.json to use ice land/takeoff videos for slots 02 and 03
- Add 7 new test checks covering the storm envelope math, habitable data contract, bundle sanity, and facade apply(); bump live types from three to four
