Mushroom groves: unclaimable moss where giant mushrooms grow slowly and glow when ready to fell

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lang/en.lang

@@ -462,6 +462,10 @@ tile.lava_info = Whatever falls in burns. Stone bridges cross it.
 tile.bridge = Wooden bridge
 tile.lavabridge = Stone bridge
 tile.mushroom = Giant mushroom
+tile.mushroom_grown = Fully grown: ready for felling.
+tile.mushroom_growing = Growing: {0}% - it can only be felled when fully grown.
+tile.grove = Mushroom grove
+tile.grove_info = Nobody can claim this moss. Giant mushrooms grow back here.
 tile.tree = Tree
 tile.plant_info = Mark it with the pick: an imp fells it for {0} wood.
 tile.drawbridge = Drawbridge
@@ -1275,6 +1279,7 @@ ed.terrain.ruby = Ruby vein
 ed.terrain.diamond = Diamond vein
 ed.terrain.steel = Steel wall
 ed.terrain.mushroom = Giant mushroom
+ed.terrain.grove = Mushroom grove
 ed.terrain.grass = Grass (above ground)
 ed.terrain.tree = Tree
 ed.place.core = Soul core