G4: gene-driven content — fruiting, harvest products, leaf color

New plant content, all driven by genes through the trait layer (no engine
change — the genetics machinery already supports it).

- ProductDef + products.json (wood, grass, berries, acorn) — what plants
  yield; localized labels (ru/en).
- New numeric genes (genes.json): GeneFruitYield, GeneFruitSeason,
  GeneHarvestAmount, GeneLeafHue, each declaring its trait via formula.
  GenomeDef carries the per-species bases (PlantSet maps them into the
  species template); PlantDef gains harvestProduct / fruitProduct.
- PlantPhenotype gains FruitYield/FruitSeason/HarvestAmount/LeafHue.
  PlantFactory tints the sprite from the leaf-hue gene (combined with the
  morph variant). Plants carry a Fruiting component; PlantFruitingSystem
  ripens fruit on mature plants during their gene-chosen season and drops
  it off-season.
- plants.json: trees give wood + acorns (autumn), bushes berries (summer),
  grass gives grass — amounts/season/hue from genes.
- 'plant <species> [seed]' console command samples a species genome and
  prints its gene-driven traits and products.

Build clean; def JSON validated; boot smoke loads the new content.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Mods/Core/Defs/plants.json

@@ -2,10 +2,12 @@
   "type": "Plant",
   "defs": [
     { "defName": "BaseTree", "abstract": true, "sizeCells": 2.0, "trunkRadiusCells": 0.28,
+      "harvestProduct": "ProductWood", "fruitProduct": "ProductAcorn",
       "genome": { "optimalLight": 0.6, "lightTolerance": 0.5, "optimalTemperature": 14, "temperatureTolerance": 16,
                   "optimalFertility": 1.4, "fertilityTolerance": 0.9, "vigor": 1.0,
                   "lifespan": 160, "dispersalRange": 2, "reproduceInterval": 14, "selfPollination": 0.2,
-                  "mutationRate": 0.05, "variantChance": 0.15, "spread": 0.08 },
+                  "mutationRate": 0.05, "variantChance": 0.15, "spread": 0.08,
+                  "fruitYield": 5, "fruitSeason": 2, "harvestAmount": 10, "leafHue": 0.30 },
       "stages": [
         { "texture": "things/plant/seed_default", "sizeCells": 0.6, "growDays": 4, "label": "plant.stage.seedling" },
         { "sizeCells": 1.2, "growDays": 9, "label": "plant.stage.sapling" },
@@ -17,20 +19,24 @@
     { "defName": "TreeGrayPineA", "parent": "BaseTree", "label": "plant.pine",  "texture": "things/plant/treegraypine/TreeGrayPineA" },
 
     { "defName": "GrassA", "label": "plant.grass", "texture": "things/plant/grass/grassa", "sizeCells": 1.2,
+      "harvestProduct": "ProductGrass",
       "genome": { "optimalLight": 0.85, "lightTolerance": 0.35, "optimalTemperature": 20, "temperatureTolerance": 12,
                   "optimalFertility": 1.0, "fertilityTolerance": 1.0, "vigor": 1.3,
                   "lifespan": 22, "dispersalRange": 3, "reproduceInterval": 3, "selfPollination": 0.8,
-                  "mutationRate": 0.06, "variantChance": 0.2, "spread": 0.1 },
+                  "mutationRate": 0.06, "variantChance": 0.2, "spread": 0.1,
+                  "harvestAmount": 2, "leafHue": 0.36 },
       "stages": [
         { "texture": "things/plant/seed_default", "sizeCells": 0.5, "growDays": 2, "label": "plant.stage.sprout" },
         { "sizeCells": 1.2, "label": "plant.stage.mature" }
       ] },
 
     { "defName": "BaseBush", "abstract": true, "label": "plant.bush", "sizeCells": 1.4,
+      "fruitProduct": "ProductBerry",
       "genome": { "optimalLight": 0.6, "lightTolerance": 0.5, "optimalTemperature": 17, "temperatureTolerance": 13,
                   "optimalFertility": 1.1, "fertilityTolerance": 1.0, "vigor": 1.0,
                   "lifespan": 60, "dispersalRange": 2, "reproduceInterval": 7, "selfPollination": 0.5,
-                  "mutationRate": 0.05, "variantChance": 0.18, "spread": 0.1 },
+                  "mutationRate": 0.05, "variantChance": 0.18, "spread": 0.1,
+                  "fruitYield": 3, "fruitSeason": 1, "harvestAmount": 3, "leafHue": 0.32 },
       "stages": [
         { "texture": "things/plant/seed_default", "sizeCells": 0.6, "growDays": 3, "label": "plant.stage.sprout" },
         { "sizeCells": 1.4, "label": "plant.stage.mature" }