Revert "fix(layout): reserve growable tree vectors up front to avoid bad_alloc"

This reverts commit 873e003c45.

native/include/lua/layout.h

@@ -144,10 +144,7 @@ public:
   // Growth doubling needs the old and new buffers live at once, which is the
   // allocation that fails first on a tight heap. One reservation covers a
   // typical screen so a build reallocates only if it genuinely gets large.
-  // 512 skips most growth-doubling reallocs during a build (a typical screen is
-  // ~300 nodes); 64 forced 4-5 doubling moves, each fragmenting the heap while
-  // old and new buffers are both live.
-  static constexpr size_t RESERVE = 512;
+  static constexpr size_t RESERVE = 64;
 
   void reset() {
     focus = NONE;
@@ -159,14 +156,6 @@ public:
     labels.clear();
     styles.clear();
     scrollState.clear();
-    // Reserve every growable vector while the heap still has a large contiguous
-    // block. A doubling realloc mid-build needs old+new live at once and throws
-    // bad_alloc on a heap the build has already fragmented -- the styles vector
-    // is what the global new-handler caught and turned into a reset. styles is
-    // sparser than nodes; labels is a byte arena.
-    labelAt.reserve(RESERVE);
-    styles.reserve(RESERVE / 2);
-    labels.reserve(1024);
     error = nullptr;
   }