GEN-4 REW erweitert: alle 3 C-Kombi + pp = REW (Julian bestätigt)

- cReduced(c) = cchm || ch; REW wenn cReduced(c0) && cReduced(c1) && pp
  (cchm/cchm, cchm/ch, ch/ch alle REW; mind. ein volles C = NICHT REW)
- Counterproof-Test: C/cchm + pp und C/ch + pp = nicht REW
- Frozen-Round-Trip-Test: PEW (ch/ch+pp) explizit ausgenommen (intentional
  shadow durch REW-Check per Julian-Regel; PEW bleibt Dropdown-Name)
Gate: build ✓  eslint ✓  vitest 95/95 ✓  e2e 148/148 ✓

gerbil-manager-web/src/genetics/__tests__/genetics.test.ts

@@ -187,7 +187,13 @@ describe('Farbschlag catalog', () => {
   it('frozen contract names round-trip to themselves (DB-key guard)', () => {
     // The first 18 are the frozen ColorVariety keys — their representative
     // genotype MUST resolve back to their own name, never a later variety.
+    // GEN-4 exception: 'Pink Eyed White (PEW)' (ch/ch+pp) now computes 'REW'
+    // because the REW engine check (both C-alleles reduced + pp) fires first.
+    // PEW stays in the catalog as a user-pickable import name; its computed
+    // farbschlag is intentionally 'REW' per Julian's extended rule.
+    const REW_SHADOWED = new Set(['Pink Eyed White (PEW)'])
     for (const entry of BASE_COLORS.slice(0, FROZEN_COUNT)) {
+      if (REW_SHADOWED.has(entry.name)) continue
       expect(genotypeToFarbschlag(representativeGenotype(entry))).toBe(entry.name)
     }
   })
@@ -538,14 +544,21 @@ describe('GEN-4: Dilute prefix, REW, no-bare-Fuchs', () => {
     expect(name('aa CC dd EE GG pp spsp rere')).toBe('Dilute Platin')
   })
 
-  it('REW: cchm/cchm + pp = REW regardless of A/D/E/G', () => {
+  it('REW: both C alleles reduced (no full C) + pp = REW — all three cases (Julian confirmed)', () => {
+    // hom cchm/cchm + pp
     expect(name('AA cchmcchm DD EE GG pp spsp rere')).toBe('REW')  // CP-Gold
     expect(name('AA cchmcchm DD ee GG pp spsp rere')).toBe('REW')  // CP-Goldfuchs
     expect(name('AA cchmcchm DD EE gg pp spsp rere')).toBe('REW')  // CP-Elfenbein
     expect(name('AA cchmcchm DD ee gg pp spsp rere')).toBe('REW')  // CP-Apricot
     expect(name('AA cchmcchm dd EE GG pp spsp rere')).toBe('REW')  // CP-dd Gold
-    // cchm/ch (het) + pp is NOT REW (only homozygous cchm/cchm qualifies)
+    // het cchm/ch + pp (Julian: also REW)
-    expect(name('AA cchmch DD EE GG pp spsp rere')).not.toBe('REW')
+    expect(name('AA cchmch DD EE GG pp spsp rere')).toBe('REW')
+    // ch/ch + pp (Julian: also REW — subsumes PEW)
+    expect(name('AA chch DD EE GG pp spsp rere')).toBe('REW')
+    expect(name('aa chch DD EE GG pp spsp rere')).toBe('REW')
+    // Counterproof: full C present → NOT REW (residual pigment)
+    expect(name('AA Ccchm DD EE GG pp spsp rere')).not.toBe('REW') // Cc[chm] + pp = Gold-like
+    expect(name('AA Cch DD EE GG pp spsp rere')).not.toBe('REW')   // Cc[h] + pp
   })
 
   it('bare Fuchs never appears — dilute-fox combinations are named specifically', () => {

gerbil-manager-web/src/genetics/catalog.ts

@@ -253,13 +253,16 @@ export function farbschlagFor(g: Genotype): FarbschlagMatch {
   if (locusToken(g, 'Sp') === 'Sp') modifiers.push('Schecke')
   if (locusToken(g, 'Re') === 'Re') modifiers.push('Rex')
 
-  // GEN-4 REW check: homozygous colourpoint (cchm/cchm) + pink-eyed (pp) = REW.
+  // GEN-4 REW check (Julian confirmed + extended): both C alleles reduced (no full 'C')
-  // This combination removes both fur pigment (C locus) and eye pigment (P locus)
+  // AND pink-eyed (pp) = REW (Rotaugenweiß), A/D/E/G-independent.
-  // regardless of A/D/E/G.  Examples: CP-Gold, CP-Goldfuchs, CP-Elfenbein, CP-Apricot.
+  //   cchm/cchm + pp → REW  (CP varieties with pink-eye)
-  // Flagged to god for confirmation (condition: cchm×cchm + p×p).
+  //   cchm/ch  + pp → REW  (het colourpoint + pink-eye)
+  //   ch/ch    + pp → REW  (this also subsumes the frozen 'Pink Eyed White (PEW)' entry)
+  // Counterproof: at least one full 'C' + pp → NOT REW (residual pigment remains).
   const [c0, c1] = resolvedPair(g, 'C')
   const [p0, p1] = resolvedPair(g, 'P')
-  if (c0 === 'cchm' && c1 === 'cchm' && p0 === 'p' && p1 === 'p') {
+  const cReduced = (c: string) => c === 'cchm' || c === 'ch'
+  if (cReduced(c0) && cReduced(c1) && p0 === 'p' && p1 === 'p') {
     const name = ['REW', ...modifiers].join(' ')
     return { name, base: null, unknown: false }
   }