Enforce seed cohesion

- Scope cached generation fields to their seed and context.
- Warm decorators and ores with their canonical generation seeds.
- Stabilize object traversal and procedural placement choices.
- Isolate smart-bore variants from shared source objects.
- Pin noise and full-engine output across generation orders.
- Verify same-jar generation through cold server restarts.

probe/src/test/resources/seed-cohesion/biomes/terrain.json

@@ -0,0 +1,18 @@
+{
+  "name": "Terrain",
+  "derivative": "minecraft:plains",
+  "vanillaDerivative": "minecraft:plains",
+  "layers": [{"palette": [{"block": "minecraft:stone"}]}],
+  "generators": [{"generator": "terrain", "min": 20, "max": 30}],
+  "decorators": [{
+    "chance": 0.61,
+    "style": {"style": "SIMPLEX", "zoom": 7},
+    "variance": {"style": "SIMPLEX", "zoom": 4},
+    "heightVariance": {"style": "SIMPLEX", "zoom": 9},
+    "forcePlace": true,
+    "stackMin": 1,
+    "stackMax": 5,
+    "palette": [{"block": "minecraft:stone"}, {"block": "minecraft:dirt"}],
+    "topPalette": [{"block": "minecraft:granite"}, {"block": "minecraft:andesite"}]
+  }]
+}

probe/src/test/resources/seed-cohesion/dimensions/cohesion.json

@@ -0,0 +1,11 @@
+{
+  "name": "Seed cohesion fixture",
+  "version": 1,
+  "mode": {"type": "OVERWORLD"},
+  "regions": ["terrain"],
+  "environment": "NORMAL",
+  "dimensionHeight": {"min": 0, "max": 64},
+  "logicalHeight": 64,
+  "fluidHeight": 10,
+  "caveProfile": {"enabled": false}
+}

probe/src/test/resources/seed-cohesion/generators/terrain.json

@@ -0,0 +1,5 @@
+{
+  "seed": 310,
+  "interpolator": {"function": "NONE", "horizontalScale": 1},
+  "composite": [{"seed": 310, "style": {"style": "SIMPLEX", "zoom": 19}}]
+}

probe/src/test/resources/seed-cohesion/regions/terrain.json

@@ -0,0 +1,6 @@
+{
+  "name": "Terrain",
+  "landBiomes": ["terrain"],
+  "seaBiomes": ["terrain"],
+  "shoreBiomes": ["terrain"]
+}