chore(dependencies): Update Midway.js and Koa dependencies

- Upgraded @midwayjs/koa to version 3.20.0
- Added explicit Koa and @types/koa dependencies
- Moved cross-env to main dependencies
- Updated start script to use cross-env for consistent environment setting

package.json

@@ -18,7 +18,7 @@
     "@midwayjs/cross-domain": "^3.16.6",
     "@midwayjs/decorator": "^3.16.2",
     "@midwayjs/info": "^3.16.6",
-    "@midwayjs/koa": "^3.16.6",
+    "@midwayjs/koa": "^3.20.0",
     "@midwayjs/logger": "^3.4.2",
     "@midwayjs/socketio": "^3.15.2",
     "@midwayjs/static-file": "^3.16.6",
@@ -48,7 +48,10 @@
     "svg2png-wasm": "^1.4.1",
     "typeorm": "^0.3.20",
    "uuid": "^10.0.0",
-    "ws": "^8.18.0"
+    "ws": "^8.18.0",
+    "cross-env": "^7.0.3",
+    "koa": "^2.15.0",
+    "@types/koa": "^2.15.0"
   },
   "devDependencies": {
     "@midwayjs/cli": "^2.1.1",
@@ -56,7 +59,6 @@
     "@types/jest": "^29.5.12",
     "@types/koa": "^2.15.0",
     "@types/node": "22",
-    "cross-env": "^7.0.3",
     "jest": "^29.7.0",
     "mwts": "^1.3.0",
     "mwtsc": "^1.11.1",
@@ -68,7 +70,7 @@
     "node": ">=12.0.0"
   },
   "scripts": {
-    "start": "NODE_ENV=production node ./bootstrap.js",
+    "start": "cross-env NODE_ENV=production node ./bootstrap.js",
     "dev": "cross-env && cross-env NODE_ENV=local TS_NODE_TYPE_CHECK=false TS_NODE_TRANSPILE_ONLY=true midway-bin dev --ts",
     "cov": "midway-bin cov --ts",
     "lint": "mwts check",