fix(electrobun): use setPosition+setSize instead of setFrame, add resize throttle

ui-electrobun/src/mainview/App.svelte

@@ -144,8 +144,13 @@
     e.preventDefault();
     e.stopPropagation();
   }
+  let resizeThrottleId = 0;
   function onResizeMove(e: MouseEvent) {
     if (!isResizing || !resizeReady) return;
+    // Throttle to ~30fps to avoid overwhelming GTK
+    const now = Date.now();
+    if (now - resizeThrottleId < 33) return;
+    resizeThrottleId = now;
     const dx = e.screenX - resizeStartX;
     const dy = e.screenY - resizeStartY;
     let { x, y, width, height } = resizeFrame;