build(npm): add babel and postcss webpack rules

static/package.json

@@ -16,12 +16,18 @@
     "flag-icons": "^7.5.0"
   },
   "devDependencies": {
+    "@babel/core": "^8.0.1",
+    "@babel/preset-env": "^8.0.2",
     "@types/bootstrap": "^5.2.11",
     "@types/node": "^26.1.0",
+    "babel-loader": "^10.1.1",
     "copy-webpack-plugin": "^14.0.0",
+    "core-js": "^3.49.0",
     "css-loader": "^7.1.4",
     "file-loader": "^6.2.0",
     "mini-css-extract-plugin": "^2.10.2",
+    "postcss": "^8.5.22",
+    "postcss-loader": "^8.2.1",
     "sass": "^1.101.0",
     "sass-loader": "^17.0.0",
     "style-loader": "^4.0.0",
@@ -30,5 +36,9 @@
     "typescript": "^6.0.3",
     "webpack": "^5.108.3",
     "webpack-cli": "^7.1.0"
-  }
+  },
+  "browserslist": [
+    "> 0.5%",
+    "last 2 versions"
+  ]
 }