feat: maximize -> full viewport + center-top; restore -> center behavior

src/ui.tsx

@@ -196,17 +196,29 @@ function Plugin () {
   }, [])
 
   function toggleWindowSize () {
-    // "Maximize" targets the visible viewport geometry (maxViewport = bounds*zoom,
-    // without subtracting header/frame). Figma clamps the request to its real window
-    // limit (depends on whether Figma UI is hidden). The real size is then measured
-    // via the iframe (window.innerWidth/Height) and shown as lastSize/gaps.
     const max = windowInfo != null ? windowInfo.maxViewport : { width: 1920, height: 1080 }
     const isMaximized =
       currentWindowSize.width >= max.width && currentWindowSize.height >= max.height
-    const next = isMaximized ? { ...MIN_WINDOW_SIZE } : { ...max }
-    setCurrentWindowSize(next)
-    emit('RESIZE_WINDOW', next)
-    refreshInfo()
+    if (!isMaximized) {
+      // Maximize: stretch to the full available viewport, then pin to center-top.
+      setCurrentWindowSize({ ...max })
+      emit('RESIZE_WINDOW', { ...max })
+      // After Figma applies the resize (and clamps to its real limit), reposition to
+      // center-top from the REAL rendered size (read from the iframe).
+      requestAnimationFrame(function () {
+        requestAnimationFrame(function () {
+          emit('DOCK_REFINE', {
+            position: 'top-center',
+            width: window.innerWidth,
+            height: window.innerHeight
+          })
+          refreshInfo()
+        })
+      })
+    } else {
+      // Restore: behave exactly like the Center button (50% viewport, centered).
+      dockWindow('center')
+    }
   }
 
   // 9 dock positions: 4 corners + 4 edges + center.