fix: add @types/superagent to dependencies (#3)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
- Added TypeScript type definitions for the `superagent` library to
enhance type safety.
- **Chores**
- Updated dependency management by moving `@types/superagent` from
`devDependencies` to `dependencies`.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

package.json

@@ -24,6 +24,7 @@
     "node": ">= 18.19.0"
   },
   "dependencies": {
+    "@types/superagent": "^8.1.9",
     "superagent": "^9.0.1"
   },
   "devDependencies": {
@@ -34,7 +35,6 @@
     "@types/express": "^5.0.0",
     "@types/mocha": "10",
     "@types/node": "22",
-    "@types/superagent": "^8.1.9",
     "body-parser": "^1.20.3",
     "cookie-parser": "^1.4.6",
     "egg-bin": "6",