scene: ES2016-safe hasOwnProperty, tighten undefined-bucket assertion, reflow bound comment

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/app/features/scene/creatures.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { BUCKET_SCALE, creatureScale, NEUTRAL_SCALE, SizeBucket } from './creatures';
+import { BUCKET_SCALE, creatureScale, SizeBucket } from './creatures';
 
 const buckets: SizeBucket[] = ['small', 'medium', 'large'];
 
@@ -17,7 +17,7 @@ describe('creature scale', () => {
 
   it('does not crash or default to medium when a non-neutral creature has no sizeBucket', () => {
     expect(creatureScale({ neutral: false })).toBeNull();
-    expect(creatureScale({ sizeBucket: undefined, neutral: false })).not.toBe(BUCKET_SCALE.medium);
+    expect(creatureScale({ sizeBucket: undefined, neutral: false })).toBeNull();
   });
 
   it('draws nothing for an unknown bucket, including inherited property names', () => {

src/app/features/scene/creatures.ts

@@ -33,5 +33,5 @@ export const BUCKET_SCALE: Readonly<Record<SizeBucket, number>> = {
 /** The draw scale, or null when nothing is drawn: a neutral creature, or a bucket that is absent or unknown. */
 export function creatureScale(c: Pick<Creature, 'sizeBucket' | 'neutral'>): number | null {
   if (c.neutral || c.sizeBucket === undefined) return null;
-  return Object.hasOwn(BUCKET_SCALE, c.sizeBucket) ? BUCKET_SCALE[c.sizeBucket] : null;
+  return Object.prototype.hasOwnProperty.call(BUCKET_SCALE, c.sizeBucket) ? BUCKET_SCALE[c.sizeBucket] : null;
 }

src/app/features/scene/world.ts

@@ -25,9 +25,9 @@ export const WORLD = {
   erodeNorm: 0.5,
   // Bound on |grad| of the phasor's cos component for the side and norm above. Libby measured a
   // sup of 6.63 at |side| = 1.5, n = 0 (CultLib PR #1 head 990521b3); 7.0 adds margin.
-  // The sup was measured, not proved. The
+  // The sup was measured, not proved. The shader passes roughness n = 0 as a literal, so the doc
-  // shader passes roughness n = 0 as a literal, so the doc envelope max(10, 1.25|side|)/(1-n)
+  // envelope max(10, 1.25|side|)/(1-n) needs no 1/(1-n) factor here; if n ever becomes nonzero,
-  // needs no 1/(1-n) factor here; if n ever becomes nonzero, divide this bound by (1 - n).
+  // divide this bound by (1 - n).
   // |value| <= 1 holds by construction (the output is a normalized phasor).
   // Typed number, not the literal 7, so callers can build variants such as { ...WORLD, phacelleGradBound: 0 }.
   phacelleGradBound: 7.0 as number,