fix: runtime Box3 scaling + Alpine null-safety

- Replaced hardcoded SPECIES_LENGTH with runtime Box3 measurement
  (model added to parent group BEFORE measuring, so full GLB
  hierarchy transforms are included in world matrices)
- All 9 species now render at correct target size (0.13-0.32u)
- Added optional chaining (?.) to all Alpine template expressions
  referencing store.selectedFish to prevent null-reference errors
- Guarded getFishValue/canBreed calls with null checks

src/main.ts

@@ -59,27 +59,10 @@ function getSpeciesUrl(sp: FishSpecies): string {
   };
   return urls[sp];
 }
-// Per-species true longest rendered extent (model units), measured
-// offline with scripts/measure-models.mjs (stride-safe rest-pose +
-// swim-clip evaluation of the actual GLB data). Fish are scaled by
-// targetLength / modelLength. This replaces the old
-// Box3.setFromObject auto-measure, which under-reports armature-scaled
-const SPECIES_LENGTH: Record<FishSpecies, number> = {
-  angelfish: 4.2139,
-  goldfish: 1.7386,
-  guppy: 2.8070,
-  betta: 1.0228,
-  blue_tang: 1.0192,
-  flower_horn: 1.0516,
-  neon_tetra: 3.6548,
-  oscar: 8.8411,
-  knifefish: 23.0140,
-};
 function fishToSpec(f: FishData): FishSpec {
   return {
     url: getSpeciesUrl(f.species),
     targetLength: f.genetics.sizeMult * 0.5,
-    modelLength: SPECIES_LENGTH[f.species],
     speed: [0.3 * f.genetics.speedMult, 0.7 * f.genetics.speedMult],
     orient: isQuaternius(f.species) ? { y: Math.PI / 2 } : undefined,
     genetics: f.genetics,