[vaprdev]

Summary

Creatures and props floated on the ground. A new src/shadow.ts grounds them with a soft contact shadow and a cast shadow away from the light.

+shade = sunShade(time, look.orb, weather.covered)
 draw creature / prop
+  groundShadow(hdr, W, H, shade, x, y, w, h, tip?, lift?)   before drawing it

Shadows are short by day, long and spreading at sunset, faint at night and contact-only under cloud; lift fades them for hops. They multiply the ground toward a sky-tinted color so they never gray it. Used in beach, city, desert, farm, jungle, prehistoric, tundra and zen; exported from the API, shown in the template and documented.

Evidence

Before (main) on the left, after on the right.

Sunset

Verification: bun run typecheck passes; CI's check job runs dev/check.ts on this branch.

Merge Danger

Door: two-way

Blast Radius: visuals

Eight wallpapers; overlapping shadows stacking darker is fixed during integration in #1.

Merged together with the other visual improvements in #1; this PR's CI screenshot check fails by design because screenshots are regenerated there.