- SmallVec<[DropEntry; 2]> replaces Vec in DropTable: zero heap allocation for
all current tiles (0 or 1 entries), spills to heap only at 3+
- DropEntry fields packed to u8 (chance_pct, min_count, max_count): ~12 bytes ->
4 bytes; derives Copy so no extra clones
- Replaced SystemTime pseudo-RNG with dig_rng(pos): PCG-style hash of world SEED
+ tile position. Deterministic per world, same dig = same roll every time
- TOML-driven drop tables: assets/drop_tables.toml (grass=5%/1-2, rock=10%/1,
dirt/air=none). TOML parsed at startup into DropTableRegistry resource
- OnceLock global map for async terrain generation tasks to access drop tables
without Bevy resource borrowing
- terrain.rs: DropTableRegistry::global_get("tile") replaces hardcoded drop_table_for
- Add TileOccupancy resource and rebuild_tile_occupancy system to track
per-tile entity counts for soft collision avoidance
- Add collision_delay to Ambulatory; entities try relative-left step on
occupied tiles, wait 1 tick, then push through
- Fix leaf canopy standability: leaves are now can_stand_in=true,
can_stand_on=false (walkable, not standable-on)
- Delete FloorTilePrefab / FixtureTilePrefab / FloorTile / FixtureTile /
TileState (all fully dead — TileMap + ChunkData are sole truth)
- Delete tile_spawns from TerrainBlob (populated but never consumed)
- Delete leaf ghost entity spawn in forestry (orphaned invisible ECS entity)
- Replace log prefab spawn with inline commands.spawn(Transform, Visibility)
- Add TileMap::remove_fixture for future digging/explosion use
- Skip collision avoidance when current tile has >2 entities (handles spawn
cluster deadlock)