feat: add correlation ids and tighten frontend security headers (#299)

* feat: add correlation ids and tighten frontend security headers

* docs: remove obsolete project setup guide

* fix: restore health config flags for compatibility

* test(frontend): align auth fetch assertions with correlation headers

backend/src/types/fastify.d.ts

@@ -22,6 +22,7 @@ declare module "fastify" {
 
 	interface FastifyRequest {
 		user?: AuthUser | null;
+		correlationId?: string;
 	}
 }