Phase 3: Alpha guardians, one per zone, back 5 hours after a defeat

- Companion mod (zone/Guardians.kt): each zone's guardian stands at the
  zone's sample point, appears when a player is within 96 blocks, stays
  within 24 blocks, is uncatchable and half again as big. Beating it in a
  battle gives every player in the battle its drops; it returns after 5
  hours of game time (Adrian: fixed spots, 5 hours). State lives in the
  world save; /cobblesurvival guardians lists it.
- tools/zone_spawns.py writes data/cobblesurvival/guardians/<zone>.json:
  the strongest walking (or swimming) Pokemon of the zone at band top + 5,
  with the drops from world/zones.json. Boss drops follow Adrian's rule:
  Icy Rocks before Sunscorch, Heat Rocks before Frostpeak.
- Goat Fur and Hoglin Hide recipes make 8 per rock, so one guardian's 3
  rocks pay for one full insulating set.
- Self-test guardian_appears_and_returns; hazard tests cleaned up; the
  zone generator reads Cobblemon's own entries from the field guide's
  hidden_spawns.

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

pack/kubejs/server_scripts/insulation.js

@@ -4,10 +4,10 @@
 //  - Goat Fur (cold insulation, Frostpeak): wool and a Heat Rock, which Sunscorch's guardian drops;
 //  - Hoglin Hide (heat insulation, Sunscorch): leather and an Icy Rock, which the guardians of the
 //    Mangrove Mire and Highland Meadows drop.
-// Cold Sweat's own armour recipes then turn these into the fur and hide sets. Placeholder amounts
-// (docs/balance.md).
+// Cold Sweat's own armour recipes then turn these into the fur and hide sets: a set takes 24, so three
+// rocks, which is one guardian's drop. Placeholder amounts (docs/balance.md).
 ServerEvents.recipes(event => {
-  event.shaped('4x cold_sweat:goat_fur', [
+  event.shaped('8x cold_sweat:goat_fur', [
     'WWW',
     'WHW',
     'WWW'
@@ -16,7 +16,7 @@ ServerEvents.recipes(event => {
     H: 'cobblemon:heat_rock'
   }).id('cobblesurvival:goat_fur')
 
-  event.shaped('4x cold_sweat:hoglin_hide', [
+  event.shaped('8x cold_sweat:hoglin_hide', [
     'LLL',
     'LIL',
     'LLL'