refactor: ♻️ change resolvspec types to build in sqltypes

README.md

@@ -151,8 +151,21 @@ pkg/merge/            Schema merging
 pkg/models/           Internal data models
 pkg/transform/        Transformation logic
 pkg/pgsql/            PostgreSQL utilities
+pkg/sqltypes/         Nullable SQL types for generated/hand-written models (see below)
 ```
 
+## Nullable Types (`pkg/sqltypes`)
+
+The `bun` and `gorm` writers can generate model structs using
+[`pkg/sqltypes`](./pkg/sqltypes/README.md) — nullable types (`SqlString`,
+`SqlInt32`, `SqlTimeStamp`, `SqlStringArray`, …) that implement
+`database/sql.Scanner`, `driver.Valuer`, and JSON/YAML/XML marshalling in one
+type, selected via `--types sqltypes`. See the
+[`pkg/sqltypes` README](./pkg/sqltypes/README.md) for the full type
+reference, or the [`bun`](./pkg/writers/bun/README.md) /
+[`gorm`](./pkg/writers/gorm/README.md) writer docs for the `--types` flag
+(`sqltypes`, `stdlib`, or `baselib`).
+
 ## Contributing
 
 1. Register or sign in with GitHub at [git.warky.dev](https://git.warky.dev)