fix(server): cannot infer without reference issue (#315)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
- We introduced additional type definitions to enhance integration and
error handling behind the scenes. These improvements promote smoother
interoperability across various components, leading to a more consistent
and reliable overall platform performance. While this update is
technical in nature, it lays the groundwork for improved system
stability and better end-user experiences. As a result, users may notice
enhanced overall performance.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: dinwwwh

packages/contract/src/index.ts

@@ -15,4 +15,5 @@ export * from './router-utils'
 export * from './schema'
 
 export { ORPCError } from '@orpc/client'
+export type { HTTPMethod, HTTPPath } from '@orpc/client'
 export type { Registry, ThrowableError } from '@orpc/shared'

packages/server/src/index.ts

@@ -21,6 +21,7 @@ export * from './router-hidden'
 export * from './router-utils'
 
 export { isDefinedError, ORPCError, safe } from '@orpc/client'
+export type { HTTPMethod, HTTPPath } from '@orpc/client'
 export { eventIterator, type, ValidationError } from '@orpc/contract'
 export type {
   ContractProcedure,
@@ -31,6 +32,7 @@ export type {
   InferSchemaInput,
   InferSchemaOutput,
   InputStructure,
+  MergedErrorMap,
   Meta,
   OutputStructure,
   Route,