fix(server-hono): reuse active Zod instance for Swagger schemas (#1224)

* fix(server-hono): keep swagger docs populated on openapi fallback

* fix(server-hono): reuse active zod instance for swagger schemas

Author: omeraplak

.changeset/smart-swagger-paths.md

@@ -0,0 +1,9 @@
+---
+"@voltagent/server-hono": patch
+---
+
+fix(server-hono): generate Swagger schemas with a single Zod instance
+
+Built-in Swagger route schemas now reuse the same schema definitions with the Zod instance selected
+by server-hono's OpenAPI compatibility layer. This avoids mixing Zod v3/v4 schema instances and
+prevents `/doc` from failing during OpenAPI generation.