Aerie and flying creatures: bats, chain gargoyles, arcane owls, ember wyrms

- New room: aerie (key Y, rooms category, campaign from mission 7); flyers sleep there
- Arrivals: aerie 4+ bats; + torture chamber gargoyles; + library owls; big aerie and treasury
  (16+ each) a rare ember wyrm; portal checks free places in lairs and aerie separately
- Flyers cross water and lava (path finding, flag, attacks), are not burnt by lava, patrol far
  when idle, attack single enemies, flee to the aerie below 25% health and rest there up to 75%
- Owls shoot arcane bolts, the wyrm breathes fire with splash damage; shots from the air
- Hovering sprites with flapping, aerie floor, perches, roosts, plinths, twig and ember nests
- Room counts are recounted on load (no longer stored); tests for flying and arrivals

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

src/ui.rs

@@ -159,7 +159,7 @@ pub enum Tool {
 }
 
 // New tools are appended so that existing key bindings ("tool<i>") keep their meaning
-pub const TOOLS: [Tool; 18] = [
+pub const TOOLS: [Tool; 19] = [
     Tool::Dig,
     Tool::Hand,
     Tool::Room(0),
@@ -178,6 +178,7 @@ pub const TOOLS: [Tool; 18] = [
     Tool::Tower(TowerKind::Cannon),
     Tool::Tower(TowerKind::Magic),
     Tool::Bridge,
+    Tool::Room(7),
 ];
 
 
@@ -198,7 +199,8 @@ pub fn tool_info(t: Tool) -> ToolInfo {
         Tool::Room(3) => ("training", T_TRAINING, Some(3)),
         Tool::Room(4) => ("library", T_LIBRARY, Some(4)),
         Tool::Room(5) => ("torture", T_TORTURE, Some(5)),
-        Tool::Room(_) => ("temple", T_TEMPLE, Some(6)),
+        Tool::Room(6) => ("temple", T_TEMPLE, Some(6)),
+        Tool::Room(_) => ("aerie", T_AERIE, Some(7)),
         Tool::Tower(TowerKind::Arrow) => ("arrow", I_ARROW, None),
         Tool::Tower(TowerKind::Cannon) => ("cannon", I_CANNON, None),
         Tool::Tower(TowerKind::Magic) => ("magic", I_MAGIC, None),
@@ -239,7 +241,7 @@ pub fn tool_cost(t: Tool, g: &Game) -> String {
 pub const CATS: [(&str, &[usize]); 6] = [
     ("cat.dig", &[0]),
     ("cat.hand", &[1]),
-    ("cat.rooms", &[2, 3, 4, 5, 6, 12, 13, 17]),
+    ("cat.rooms", &[2, 3, 4, 5, 6, 12, 13, 18, 17]),
     ("cat.towers", &[14, 15, 16]),
     ("cat.spells", &[9, 10, 11]),
     ("cat.orders", &[8, 7]),