[Feature] Support Lance file format

### Search before asking

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

### Motivation

Apache Paimon Java supports Lance as a data file format through the paimon-lance module. Paimon C++ currently cannot read or write tables configured with file.format=lance, which prevents Java and C++ engines from interoperating on those tables.

### Solution

Add optional Lance file format support to Paimon C++, aligned with the Java implementation and Lance 0.39.0:

- register a Lance file format factory behind a disabled-by-default CMake option;
- support reading and writing Lance files through the existing file format interfaces;
- support column projection, precise row selection, row counts, and file row-id reporting;
- validate the same supported and unsupported logical types as Java;
- add C++ round-trip tests and Java/C++ compatibility fixtures in both directions.

The implementation should follow the existing Mosaic Rust FFI integration and lifecycle patterns.

### Anything else?

Java reference module: https://github.com/apache/paimon/tree/master/paimon-lance

### Are you willing to submit a PR?

- [x] I am willing to submit a PR!

Start by reading the existing Mosaic Rust FFI integration and lifecycle patterns, then compare the Java reference module at paimon-lance and inspect the existing file format interfaces. Done means an optional disabled-by-default CMake integration supports Lance reads and writes, required projections and row selection, row metadata, logical-type validation, round-trip tests, and Java/C++ compatibility fixtures.

Written by the indexing model from the issue text.