- Nebula gas layer: soft coloured cloud sprites at depth 3, tinted with a
per-system palette color assigned deterministically at galaxy generation
(SystemGenerator stamps content.atmosphere.color). Only nebula-type
systems render it; all other types are untouched.
- Ripple effect: a full-screen WebGL composite on the world camera that
displaces the starfield and world objects while the HUD stays crisp via
a new UI/world camera split (UiCameras.js). Data-driven per archetype in
data/systems.json (nebula = ripple, all others = none). Canvas fallback
degrades to no effect.
- Demo mode: ?fx=<type> URL param retargets the run to the richest system
of that archetype, fully charted with all gates active, for judging the
effect in isolation.
- New ice and lava planet art (slots 9–14 in planets.png) replacing the
placeholder terran/rocky/gas reuse.
- Node test suites for the nebula palette/determinism/cloud texture and
the ripple math/data contract/shader/facade (50+ checks, bare Node).
