Adaptor for fastify@v5

[MarioSimou]

Feature description

Currently, PostGraphile supports Fastify version 4 only. However, with the recent release of Fastify version 5, we aim to extend our support to include this latest version

Supporting development

I [tick all that apply]:

• am interested in building this feature myself
• am interested in collaborating on building this feature
• am willing to help testing this feature before it's released
• am willing to write a test-driven test suite for this feature (before it exists)
• am a Graphile sponsor ❤️
• have an active support or consultancy contract with Graphile

[benjie]

The main thing when doing this is to ensure that the fastifyv5 request context entry is registered; it should look like:

crystal/grafast/grafserv/src/servers/fastify/v4/index.ts

Lines 28 to 37 in 1942056

	declare global {
	namespace Grafast {
	interface RequestContext {
	fastifyv4: {
	request: FastifyRequest;
	reply: FastifyReply;
	};
	}
	}
	}

You code should not import from fastify at all - only types should be imported.