References #3211.
The core `col()` camelCase integration coverage requested by #3211 is already on `main` from #4493. This PR adds the adjacent raw-SQL table-surface regressions that were previously uncovered:
- unquoted `where("camelCase = 1")`
- `update` and `delete` with unquoted camelCase predicates
- `mergeInsert` with a camelCase join key, including matched-update and not-matched-insert input
- `addColumns` `valueSql` referencing a camelCase column
- `createIndex` on a camelCase column
These are characterization tests for the existing local-backend behavior. They do not add `col()` coverage or require a live remote service.