Biome Cleaner

Fixed

• Spawn-area chunks could be skipped on servers using parallel world-gen mods (e.g. C2ME). The Overworld-only check from 1.1.2 armed itself when the server finished starting, but mods that generate chunks in parallel could begin spawn-area generation a moment earlier. Any Overworld chunks created in that brief window slipped past the cleaner and stayed unprocessed forever — usually invisible, but it left tiny micro-biomes intact near spawn on freshly-generated worlds. The check now lets chunks through during that startup window (only the Overworld is force-generated at startup, so this can't accidentally touch the Nether or End) and tightens to Overworld-only as soon as the server finishes starting.
• Surface block correction in cave entrances now correctly only runs in the Overworld. The cave-carver fix from 1.1.0 (which makes carved surfaces use the cleaned-up biome instead of the raw one) was running in every dimension, not just the Overworld. In the Nether and End that meant carvers were reading the chunk palette where they expected to read the raw biome source, with no defined behaviour. It's gated on the Overworld now, matching the rest of the cleanup pipeline.

Changed

• Overworld detection is now exact instead of heuristic. 1.1.2 identified Overworld-like dimensions by scanning their biome list for minecraft:plains or minecraft:forest. That worked for vanilla but could misclassify modded "skyland"-style dimensions that happened to include either biome. The mod now records the actual Overworld biome source the moment the server is ready and matches against it directly. Modded dimensions are no longer accidentally picked up — if you have a modded dimension you genuinely want cleaned, that needs to become an explicit opt-in (planned for a future release).
• Default allowIntraGroupReplacement in common.toml is now empty. The setting still works for back-compat, but the modern, richer way to say "let oceans replace each other" is intraGroupPreference in advanced.json, which the stock config has shipped since 1.1.0 with oceans set to "preferred" (legality + preserve mid-sized lakes + small-puddle fallback). Listing oceans in both places was redundant. Existing configs that already set allowIntraGroupReplacement continue to work unchanged; freshly-generated configs simply won't have the legacy line. The TOML comment now points at the advanced-config setting.