[Feature] Leverage the file index in lookup process to skip file

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/paimon/issues) and found nothing similar.

### Motivation

During the Paimon lookup process, the local IO can be a bottleneck. It would be beneficial to utilize the file index to skip unnecessary file loading.

### Solution

_No response_

### Anything else?

_No response_

### Are you willing to submit a PR?

- [X] I'm willing to submit a PR!

The issue only identifies the Paimon lookup process and its file index; it names no files, tests, or concrete solution. Start by locating the lookup and file-index entry points, then establish which unnecessary file loads can be skipped and add coverage demonstrating the expected behavior.

Written by the indexing model from the issue text.