Add new OpenAPI 2.0 and 3.0 specifications, including comprehensive type definitions and example files. Update .gitignore and bunfig.toml, and remove obsolete MIGRATION.md. Enhance README with additional usage examples and clarify type definitions.

3.1/data-types/index.ts

@@ -0,0 +1,9 @@
+export type { ArraySchema } from "./array";
+export type { BooleanSchema } from "./boolean";
+export type { CompositionSchema } from "./composition";
+export type { IntegerSchema } from "./integer";
+export type { NullSchema } from "./null";
+export type { NumberSchema } from "./number";
+export type { ObjectSchema } from "./object";
+export type { ReferenceSchema } from "./reference";
+export type { StringSchema } from "./string";