refactor: completely rewrite SqlTemplate with intelligent SQL parsing and batching

[bercianor]

No description provided.

[dieppa]

Really good start and a solid foundation (the intent is clear and the tests are a great base).

I don’t think we can merge this approach as it stands, mainly because it rewrites SQL and that can break semantics.

Given the long tail of edge cases, I’d prefer we reuse a battle-tested OSS splitter instead (either as a dependency, or by forking/embedding the relevant code so we own it). I’m totally fine maintaining a fork if that’s the direction we choose.

Also: I like where this is going — the end goal should include supporting procedures / blocks, but we can treat that as a v2 once the DDL/DML splitting is rock-solid.