diff --git a/package.json b/package.json
index c71412b..8d53429 100644
--- a/package.json
+++ b/package.json
@@ -44,6 +44,6 @@
     "vite": "^8.0.4"
   },
   "engines": {
-    "node": ">=22.12.0"
+    "node": ">=20.19.0 || >=22.12.0"
   }
 }
diff --git a/src/components/editor/EditorPage.tsx b/src/components/editor/EditorPage.tsx
index a3a46ff..7ef8e4b 100644
--- a/src/components/editor/EditorPage.tsx
+++ b/src/components/editor/EditorPage.tsx
@@ -252,8 +252,6 @@ export function EditorPage(): React.JSX.Element {
         newMapNodes[nodeIndex] = updatedNode;
         return { ...prev, mapNodes: newMapNodes };
       });
-      setUndoCount((prev) => prev + 1);
-      console.log("Node transformed:", nodeIndex);
     },
     [sceneData],
   );
diff --git a/src/components/editor/MapViewer.tsx b/src/components/editor/MapViewer.tsx
index 08a9495..d733555 100644
--- a/src/components/editor/MapViewer.tsx
+++ b/src/components/editor/MapViewer.tsx
@@ -40,7 +40,6 @@ export default function MapViewer({
 
   const handleTransformMouseUp = () => {
     isTransforming.current = false;
-    onTransformEnd?.();
 
     if (selectedNodeIndex !== null) {
       const obj = objectsMapRef.current.get(selectedNodeIndex);
@@ -53,9 +52,12 @@ export default function MapViewer({
           rotation: [obj.rotation.x, obj.rotation.y, obj.rotation.z],
           scale: [obj.scale.x, obj.scale.y, obj.scale.z],
         };
+        // Call onNodeTransform BEFORE onTransformEnd so history captures final state
         onNodeTransform?.(selectedNodeIndex, updatedNode);
       }
     }
+
+    onTransformEnd?.();
   };
 
   const [selectedObject, setSelectedObject] = useState<THREE.Object3D | null>(
@@ -91,11 +93,7 @@ export default function MapViewer({
       <group
         onClick={(e: unknown) => {
           (e as { stopPropagation?: () => void }).stopPropagation?.();
-          if (
-            !(window as unknown as { isTransforming?: boolean }).isTransforming
-          ) {
-            onSelectNode(null);
-          }
+          onSelectNode(null);
         }}
       >
         {sceneData.mapNodes.map((node, index) => {
@@ -230,11 +228,7 @@ function ModelNodeWithRef({
       object={instance}
       onClick={(e: unknown) => {
         (e as { stopPropagation?: () => void }).stopPropagation?.();
-        if (
-          !(window as unknown as { isTransforming?: boolean }).isTransforming
-        ) {
-          onSelectNode(index);
-        }
+        onSelectNode(index);
       }}
       onPointerEnter={(e: unknown) => {
         (e as { stopPropagation?: () => void }).stopPropagation?.();
@@ -292,11 +286,7 @@ function FallbackNodeWithRef({
       scale={node.scale}
       onClick={(e: unknown) => {
         (e as { stopPropagation?: () => void }).stopPropagation?.();
-        if (
-          !(window as unknown as { isTransforming?: boolean }).isTransforming
-        ) {
-          onSelectNode(index);
-        }
+        onSelectNode(index);
       }}
       onPointerEnter={(e: unknown) => {
         (e as { stopPropagation?: () => void }).stopPropagation?.();
diff --git a/vite.config.ts b/vite.config.ts
index 038d0d6..dbdf65d 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -2,9 +2,14 @@ import { defineConfig } from "vite";
 import react from "@vitejs/plugin-react";
 import path from "node:path";
 import fs from "node:fs";
+import { fileURLToPath } from "node:url";
 import type { ViteDevServer } from "vite";
 import type { IncomingMessage, ServerResponse } from "http";
 
+const __dirname = fileURLToPath(new URL(".", import.meta.url));
+
+const MAX_MAP_PAYLOAD_BYTES = 1024 * 1024; // 1MB limit
+
 const saveMapPlugin = () => ({
   name: "save-map-api",
   configureServer(server: ViteDevServer) {
@@ -12,20 +17,52 @@ const saveMapPlugin = () => ({
       "/api/save-map",
       async (req: IncomingMessage, res: ServerResponse) => {
         if (req.method !== "POST") {
-          res.writeHead(405).end();
+          res.writeHead(405, { "Content-Type": "application/json" });
+          res.end(JSON.stringify({ error: "Method not allowed" }));
           return;
         }
 
         let body = "";
-        req.on("data", (chunk: Buffer) => (body += chunk.toString()));
-        req.on("end", () => {
+        let bodySize = 0;
+        let requestAborted = false;
+
+        req.on("data", (chunk: Buffer) => {
+          if (requestAborted) return;
+          bodySize += chunk.length;
+          if (bodySize > MAX_MAP_PAYLOAD_BYTES) {
+            requestAborted = true;
+            res.writeHead(413, { "Content-Type": "application/json" });
+            res.end(JSON.stringify({ error: "Payload too large" }));
+            req.destroy();
+            return;
+          }
+          body += chunk.toString();
+        });
+
+        req.on("error", (err: Error) => {
+          if (!res.headersSent) {
+            res.writeHead(400, { "Content-Type": "application/json" });
+            res.end(JSON.stringify({ error: err.message }));
+          }
+        });
+
+        req.on("end", async () => {
+          if (requestAborted) return;
+
           try {
+            const parsedBody = JSON.parse(body);
             const mapPath = path.resolve(__dirname, "public/map.json");
-            fs.writeFileSync(mapPath, body);
+            await fs.promises.writeFile(
+              mapPath,
+              JSON.stringify(parsedBody, null, 2),
+              "utf8",
+            );
             res.writeHead(200, { "Content-Type": "application/json" });
             res.end(JSON.stringify({ success: true }));
           } catch (err) {
-            res.writeHead(500).end(
+            const statusCode = err instanceof SyntaxError ? 400 : 500;
+            res.writeHead(statusCode, { "Content-Type": "application/json" });
+            res.end(
               JSON.stringify({
                 error: err instanceof Error ? err.message : "Unknown error",
               }),
@@ -36,7 +73,6 @@ const saveMapPlugin = () => ({
     );
   },
 });
-import { fileURLToPath } from "node:url";
 
 export default defineConfig({
   plugins: [react(), saveMapPlugin()],