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

首先阅读链接的 Databend 博客文章和相关 issue #1558，然后检查 lexer 和 token 所有权路径，以确定字符串在哪里被复制。完成的标准是减少可避免的字符串复制，同时保持 parser 行为不变，并使用项目现有的测试或 benchmark 验证性能影响。

由索引模型根据 Issue 内容生成。