Cobblemon Survival Pack: phases 0-2 and Phase 3 zones and hazards

Free NeoForge 1.21.1 modpack on Cobblemon 1.8.4 built with packwiz, plus
the Kotlin companion mod (cobblesurvival) and its built-in data pack.

- Phase 0: packwiz pack with Modrinth/CurseForge cross-links, build and
  export tooling, Prism instance sync, test server with smoke checks.
- Phase 1: Poke Ball shaped island (WorldGen Editor preset, seed isle-26),
  Adrian's biome list, no natural ore, structures without ore or vanilla
  mobs, no Nether portals, world template builder and world report.
- Phase 2: permadeath (CobbleHardcoreMon plus the companion mod's gap
  fixes), Revival Charm, expensive Healing Machine, Lootr refreshing
  loot, in-game self-tests on Minecraft's GameTest framework.
- Phase 3 so far: 14 zones with their own spawn pools and level bands
  (tools/zone_layout.py, tools/zone_spawns.py, "zone" spawn condition),
  Cold Sweat heat and cold as gates with boss-drop insulation recipes,
  spawn survey and hazard self-tests in tools/quick_check.py.

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

tools/pokeball_preset.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+"""Write the WorldGen Editor preset for a Poké Ball-shaped island.
+
+  * Ball: one round island with a smooth coast.
+  * Band: two flat-ended ocean strips across the middle, west and east of the
+    button, so the ball splits into a top and a bottom half.
+  * Button: a ring channel of overlapping small ocean circles around a round
+    centre island (where the world spawn lands).
+
+All sizes are in blocks and are placeholders until Adrian approves the
+island (docs/balance.md).
+
+Usage: tools/pokeball_preset.py [--radius 1500] [--band 160] [--button 280] [--ring 120]
+"""
+import argparse
+import json
+import math
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+PRESET = ROOT / "pack/config/worldgen_editor/presets/cobblesurvival_island.json"
+
+
+def ocean(name, x, z, rx, rz, shape_power=2.0):
+    return {"type": "ocean", "name": name, "x": round(x), "z": round(z), "radius_x": round(rx), "radius_z": round(rz),
+            "shape_power": shape_power, "roughness": 0.02, "shore_width": 0.12, "temperature": "standard",
+            "noise": {"seed": name.lower().replace(" ", "_"), "scale": 2.0}}
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    parser.add_argument("--radius", type=int, default=1500, help="radius of the ball")
+    parser.add_argument("--band", type=int, default=160, help="width of the channel across the middle")
+    parser.add_argument("--button", type=int, default=280, help="radius of the centre island")
+    parser.add_argument("--ring", type=int, default=120, help="width of the ring channel around the button")
+    args = parser.parse_args()
+
+    entries = [{
+        "type": "island", "name": "Ball", "x": 0, "z": 0, "radius": args.radius,
+        "shape_power": 2.0, "roughness": 0.03, "shore_width": 0.1, "temperature": "standard",
+        "noise": {"seed": "ball", "scale": 2.0, "first_octave": -1, "amplitudes": [1.0, 0.45, 0.18]},
+    }]
+    ring_mid = args.button + args.ring / 2
+    # The band runs from the middle of the ring to just past the coast on each side.
+    band_inner, band_outer = ring_mid, args.radius * 1.05
+    half = (band_outer - band_inner) / 2
+    for side, sign in (("west", -1), ("east", 1)):
+        entries.append(ocean(f"Band {side}", sign * (band_inner + half), 0, half, args.band / 2, shape_power=6.0))
+    # Circles overlapping by about half their size, so the ring has no gaps.
+    circle = args.ring / 2
+    count = math.ceil(2 * math.pi * ring_mid / circle)
+    for i in range(count):
+        angle = 2 * math.pi * i / count
+        entries.append(ocean(f"Ring {i + 1}", ring_mid * math.cos(angle), ring_mid * math.sin(angle), circle, circle))
+
+    PRESET.write_text(json.dumps({"outer_ocean": "minecraft:deep_ocean", "entries": entries}, indent=2) + "\n")
+    print(f"wrote {PRESET.relative_to(ROOT)}: ball r{args.radius}, band {args.band}, "
+          f"button r{args.button}, ring {args.ring} ({count} circles)")
+
+
+if __name__ == "__main__":
+    main()