0.326.0

This release fixes introspection for custom schema directives.

Schema directives attached to types, fields, arguments, and other schema elements
now appear in standard GraphQL introspection. Schema explorers, IDEs, code
generators, and other tools can discover each directive's description, arguments,
allowed locations, repeatability, and any input types it uses. Federation directives,
including generated @link and @composeDirective applications, are discoverable
in the same way.

Federation directives and custom composed directives used on field arguments are
also included in the generated subgraph metadata, so routers can recognize those
argument annotations without additional schema configuration.

A directive reused across the schema is defined only once. Input, enum, and scalar
types referenced by directive arguments are now part of the schema and may appear
in generated SDL even when they are not used by fields.

Because these directives and argument types are now part of the runtime schema,
their GraphQL names must be unique. Schema construction reports a clear error when
different directive definitions share a name, a custom directive replaces a
built-in directive such as @skip, or a directive argument type conflicts with
another schema type. Compatible custom @oneOf definitions continue to use
GraphQL's built-in directive. Strawberry now also resolves attached directive
argument annotations during schema construction, so unresolved forward references
are reported when the schema is created instead of later when its SDL is printed.

This release was contributed by @patrick91 in #4598