feat(bt): Add wait and whilst, rename leaf to action

examples/tetris/main.ts

@@ -3,11 +3,11 @@
 // Architecture:
 //   Behaviour Tree (buildTree) — controls game flow:
 //     parallel
-//       ├── gravityTick (leaf)    — generator loop, auto-drop piece on timer
+//       ├── gravityTick (action)    — generator loop, auto-drop piece on timer
 //       └── cycle
 //             └── seq (sequential)
-//                   ├── handleInput (leaf)  — reads queued commands
-//                   └── render (leaf)       — draws via blessed
+//                   ├── handleInput (action)  — reads queued commands
+//                   └── render (action)       — draws via blessed
 //
 //   CommandQueue — processes input:
 //     Keyboard → spawn command entities → CommandQueue.execute()
@@ -22,10 +22,11 @@
 import { World } from "../../src/index";
 import {
   buildTree,
-  leaf,
+  action,
   parallel,
   cycle,
   sequential,
+  whilst,
 } from "../../src/bt/index";
 import { CommandQueue } from "../../src/commands/index";
 
@@ -73,11 +74,11 @@ pieces.spawnPiece();
 const runner = buildTree(
   world,
   parallel([
-    leaf(function* gravityTick() {
-      while (true) {
-        const dt: number = yield;
+    whilst(
+      () => true,
+      action((_world, _entity, dt) => {
         if (world.hasSingleton(GameOver) || world.hasSingleton(Paused)) {
-          continue;
+          return;
         }
         const timer = world.getSingleton(TickTimer);
         timer.accumulator += dt;
@@ -93,14 +94,14 @@ const runner = buildTree(
             }
           }
         }
-      }
-    }),
+      }),
+    ),
     cycle(
       sequential([
-        leaf(() => {
+        action(() => {
           commands.execute();
         }),
-        leaf(() => {
+        action(() => {
           render(world, ui);
         }),
       ]),