Wood: giant mushrooms underground, felled by imps; wooden bridges and doors cost wood

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

src/map.rs

@@ -70,6 +70,8 @@ pub enum Kind {
     Altar,      // room: sacrifices
     Drawbridge, // bridge that can be raised (res: see DB_RAISED, DB_AUTO, DB_LAVA)
     Obsidian,   // lava cooled by frost: walkable until it melts again
+    Mushroom,   // giant mushroom on open ground: imps fell it for wood (grows back)
+    Tree,       // tree above ground: imps fell it for wood
 }
 
 // drawbridge state in Tile::res
@@ -103,7 +105,7 @@ pub struct River {
 }
 
 // order matters for the packed savegame codec: only append new kinds
-const KINDS: [Kind; 36] = [
+const KINDS: [Kind; 38] = [
     Kind::Rock,
     Kind::Earth,
     Kind::Gold,
@@ -140,6 +142,8 @@ const KINDS: [Kind; 36] = [
     Kind::Altar,
     Kind::Drawbridge,
     Kind::Obsidian,
+    Kind::Mushroom,
+    Kind::Tree,
 ];
 
 // treasures (veins, treasury content, imp loads): 0 gold, 1 silver, 2 ruby, 3 diamond
@@ -223,7 +227,11 @@ impl Tile {
         matches!(self.kind, Kind::Rock | Kind::Earth | Kind::Gold | Kind::Silver | Kind::Ruby | Kind::Diamond | Kind::Steel)
     }
     pub fn diggable(&self) -> bool {
-        matches!(self.kind, Kind::Earth | Kind::Gold | Kind::Silver | Kind::Ruby | Kind::Diamond | Kind::Steel)
+        matches!(self.kind, Kind::Earth | Kind::Gold | Kind::Silver | Kind::Ruby | Kind::Diamond | Kind::Steel | Kind::Mushroom | Kind::Tree)
+    }
+    // a giant mushroom or a tree: felled like a wall is dug, gives wood
+    pub fn plant(&self) -> bool {
+        matches!(self.kind, Kind::Mushroom | Kind::Tree)
     }
     // the treasure of a vein (None for everything else)
     pub fn vein(&self) -> Option<u8> {
@@ -751,6 +759,8 @@ impl Map {
                 Kind::Gold | Kind::Silver | Kind::Ruby | Kind::Diamond => Some(12),
                 Kind::Rock | Kind::Core | Kind::Tower | Kind::Water | Kind::Lava => None,
                 Kind::Door => Some(10),
+                Kind::Mushroom | Kind::Tree => Some(6),
+                Kind::Drawbridge if tl.res & DB_RAISED != 0 => None,
                 _ => Some(1),
             }
         }