Update Dependencies and Fix Tests

* Update `@modelcontextprotocol/sdk` to version `1.11.2`
* Add `node-fetch` with version `2.7.0`
* Replace `global.fetch` with `fetch` in test files and mock `node-fetch`
* Update `package-lock.json` and `package.json`, and add `@types/node-fetch` to devDependencies

Author: suekou