Improve performance by reducing string copies

@Omega359 [mentioned in discord](https://discord.com/channels/885562378132000778/1344430130252218439/1415763431516278794) a blog post by the Databend folks about how they wrote a replacement of sqlparser-rs for their system

https://www.databend.com/blog/category-engineering/2025-09-10-query-parser/

One thing they cite is the fact that sqlparser-rs often copies strings, even when this could be avoided

If anyone cares, we can probably avoid copying strings, someone just has to care enough to thread the lifetime information through all the tokens (or maybe use an Arc w/ an offset)

@AdamGS mentioned he might be interested in trying this

This could possibly be related to another ticket here:
- https://github.com/apache/datafusion-sqlparser-rs/issues/1558

Empieza leyendo la publicación del blog de Databend enlazada y el issue #1558 relacionado; después, inspecciona las rutas del lexer y de ownership de los tokens para identificar dónde se copian las cadenas. Se considera terminado cuando se hayan reducido las copias de cadenas evitables, se conserve el comportamiento del parser y se valide el impacto en el rendimiento con las pruebas o benchmarks existentes del proyecto.

Escrito por el modelo de indexación a partir del texto del issue.