Beyond The End - Optimization and Fixes

    Add worldgen profiling tools and output-identical worldgen optimizations

    Fixes
    - WorldGenRegionNoDropsMixin: never drop items when a feature destroys a block
      during worldgen; loot conditions read the real level from a worldgen thread
      and could deadlock the server thread.
    - BrewingRecipeRegistryThreadSafeMixin: synchronize Forge's brewing recipe list.

    Optimizations (toggle with /bteopt genopt on|off; verify against vanilla with
    /bteopt genopt verify on|off)
    - Skip tryGenerateStructure for structures whose biomes the dimension's biome
      source can never produce (1.19.2 tries every structure set everywhere and
      only checks the biome after finding a generation point).
    - Surface rules: answer biome lookups from a per-chunk cell cache handed to
      SurfaceRules.Context, with a shortcut when all eight candidate cells share
      a biome. Same arithmetic and order as BiomeManager.getBiome.
    - Reuse a chunk's NoiseChunk after the proto chunk is unloaded and reloaded
      mid-generation (LRU per RandomState, new worlds only).
    - Cache minecraft:end_islands heights per (x / 8, z / 8).
    - Cache ServerLevel.getUncachedNoiseBiome per quart position.
    - Cache a chunk's min build height and height in the chunk.

    Debug tools (all off unless started)
    - /bteopt genstats: per-phase, feature, structure, structure start, surface
      and noise detail timings, worldgen mailbox occupancy, main thread breakdown,
      Quark generator timings and grouped call traces.
    - /bteopt genprof: sampling profiler for worldgen threads (collapsed stacks).
    - /bteopt nbtstats: structure NBT load and DFU timing.
    - /bteopt genopt noisehash: per-chunk block hash after the noise fill.