import/no-unresolved can't detect the root package

Node.js can do this:

```js
// in package foo, in test script:
import foo from "foo"; // import itself for test!
```

It seems import/no-unresolved can't handle this.

Start by reproducing the package self-import example with the import/no-unresolved rule in a Node.js package, then trace the rule's module-resolution entry point. Done means the package's own import is accepted while genuinely unresolved imports are still reported.

Written by the indexing model from the issue text.