Rework how Ruins and Lunar Grotto/Archives generates

[Milordo]

Full discussion and explanations here --->

Short summary, during your future projects of the new fumarole biomes and Ruins reworks, please consider:
1) Moving Stalagmite Terrain biome to the Ruins. Maybe also implement it as the official entrance to the Ruins now, instead of the mud biome full of lightbulbs.
2) Removing the nightmare fissures from Rocky Plains and Bat Caves, or simply move them to the Ruins.
3) Fixing the entire Ruins gen issues.
4) Moving Fumarole biome in the Ruins. 
5) Atrium should spawns randomly ONLY on Ruins biomes (which also includes point 1) and 4) ).
6) A new big cave ceiling now blocks the path to Lunar Grotto, whirlpool generates only inside or near Lunar Island and is now the only main entrance to the Lunar Grotto, new various exits. I advise for this precise point to read the post.  
 

Edited October 5, 2025 by Milordo

[Milordo]

Edited the last point due to better solutions founded.

Edited October 5, 2025 by Milordo