AW 0.9.2 - Worldgen Deadlock Fix

Fixes the ServerHangWatchdog crash introduced by TAW 0.9.1's surface-habitat guard.

Root cause

During Tellus chunk generation, vanilla chunk-generation animal spawning can run on a world-generation worker thread. TAW 0.9.1 called ServerLevel#getHeight() from SpawnPlacementCheck to decide whether surface-only fauna were too deep underground. That method can synchronously request a FULL chunk from ServerChunkCache. During generation this can create a circular wait:

worldgen worker -> waits for ServerChunkCache/full chunk server thread -> waits for worldgen worker watchdog -> terminates the server

Fix

• Surface-habitat heightmap checks are skipped for CHUNK_GENERATION spawns.
• Runtime NATURAL/EVENT/etc. spawns keep the 0.9.1 cave/surface guard.
• Geographic filtering and population caps remain active during chunk generation.
• No extra ticks, scans, chunk loads, or persistent state are added.
• No network payload changed. NETWORK_PROTOCOL_VERSION remains 1, so the same client/server backward-compatibility policy remains intact.