Phase 4 play-test fixes: deep caves, fuller cave spawns, strays, shared loot

From Adrian's play-test (2026-10-30):
- The Deep Dark no longer fills the deepslate layer: world/biomes.json
  splits it by temperature (Deep Dark under cold and temperate land,
  basalt deltas under the hottest, ordinary caves between); at y -52 it
  drops from 30 % to 14 % of the land, basalt 7 %.
- Cave zones fill up to their targets with lines whose primary type fits
  the cave; top stages spawn up to the band's top (Deep Dark Lv 60, Basalt
  70); no time-of-day conditions underground.
- Wild Pokemon more than 10 levels above the band of the zone they
  wander into despawn (zone/Wanderers.kt).
- Loot is shared: all players in one scoreboard team, Lootr team_loot.
- Basalt ore nodes reach the deep basalt.
Self-tests strays_despawn and loot_is_shared; the catching rules from the
previous commit are now tested too. Template rebuilt (world check passed),
island quick check passed (36 self-tests and the restart test).
Shoulder Pokemon noted for Phase 5.

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

mod/src/main/kotlin/dev/cobblesurvival/CobbleSurvival.kt

@@ -12,8 +12,10 @@ import dev.cobblesurvival.progress.Gates
 import dev.cobblesurvival.progress.Progress
 import dev.cobblesurvival.selftest.SelfTest
 import dev.cobblesurvival.world.OnlyPokemon
+import dev.cobblesurvival.world.SharedLoot
 import dev.cobblesurvival.zone.Guardians
 import dev.cobblesurvival.zone.LevelPressure
+import dev.cobblesurvival.zone.Wanderers
 import dev.cobblesurvival.zone.ZoneCondition
 import dev.cobblesurvival.zone.ZoneHazards
 import dev.cobblesurvival.zone.Zones
@@ -68,6 +70,8 @@ class CobbleSurvival {
         Gates.register()
         OreNodes.register()
         Catching.register()
+        Wanderers.register()
+        SharedLoot.register()
         ZoneHazards.register()
         LevelPressure.register()
         SelfTest.register()