add(dev-dependencies): add eslint and vscode env setting

.vscode/settings.json

@@ -0,0 +1,25 @@
+{
+  // Formatting
+  "editor.formatOnSave": true,
+  "editor.defaultFormatter": "esbenp.prettier-vscode",
+  "eslint.workingDirectories": [{ "mode": "auto" }],
+  // ESLint auto-fix on save
+  "editor.codeActionsOnSave": {
+    "source.fixAll.eslint": "explicit",
+    "source.organizeImports": "explicit"
+  },
+  "npm.autoDetect": "on",
+
+  // Auto import behavior
+  "typescript.preferences.importModuleSpecifier": "non-relative",
+  "javascript.preferences.importModuleSpecifier": "non-relative",
+
+  // Enable ESLint for TS/JS
+  "eslint.validate": [
+    "javascript",
+    "javascriptreact",
+  ],
+
+  // Prevent conflicts with Prettier + ESLint
+  "prettier.requireConfig": true,
+}