Cryptid Core Co Field Operations

0.7.0-b — Stage 7b: Deer Casts + Jungle Rework + Structure Expansion + Crash Fix

- REWORK: Jungle Bigfoot (from 7a) split in two. The green morph is now
  "Swamp Bigfoot" and lives in swamps + mangrove swamps. The new Jungle
  Bigfoot is a brown Bigfoot with vines draped across shoulders, chest,
  and head — lives in jungles / sparse jungle / bamboo jungle. Elders
  are still Silver. Saved worlds keep their variant bytes intact.
- NEW: deer footprints — every deer stamps variant-specific hoof prints
  on the same 5-block stride as Bigfoots.
- NEW: deer plaster casts — pour plaster on a hoof print, wait 30s, collect
  a variant-specific Deer Footprint Cast trophy.
- NEW: cast collection now split into Bigfoot / Deer / Originals sub-tabs
  inside the Casts view.
- CHANGE: all four buildings (campsite, boat house, field station,
  abandoned station) now spawn across all forest-type biomes.
- CHANGE: guaranteed White Bigfoots only spawn at boat houses in birch +
  snowy biomes now. Boat houses elsewhere generate empty.
- CHANGE: field station cabin, campsite cabin, and boat house shack got
  a first pass of porches, roofs, and window trims. Full interior polish
  is still pending.
- FIX: chunk-load crash from far-chunk writes in older structure features.
  Retrofitted 126 write sites across five features with the same bounds
  guards the boat house has used since Stage 6.