feat: add TypeRT remote gateway infrastructure

packages/client/connection/src/rpc.ts

@@ -0,0 +1,59 @@
+/** Generic unary RPC contracts shared by the Host and Client Connection halves. */
+
+import type { RpcResult } from '@deepseek-ai/dsh-host-apiproxy/api'
+
+/** Trust fence applied before a Host RPC channel reaches its handler. */
+export type ConnectionRpcAuthority = 'trusted-host' | 'loopback'
+
+/** Registration policy for one logical RPC channel. */
+export interface ConnectionRpcHandlerOptions {
+  /** Browser authority accepted by every endpoint in this channel. */
+  readonly authority: ConnectionRpcAuthority
+}
+
+/** Handler invoked after Connection has decoded the transport envelope. */
+export type ConnectionRpcHandler = (
+  endpoint: string,
+  payload: unknown,
+  signal: AbortSignal,
+) => Promise<RpcResult<unknown>>
+
+/** Host registry for logical RPC channels carried by the current transport. */
+export interface HostConnectionRpc {
+  /**
+   * Register one absolute channel prefix and its trust policy.
+   * @param channel - absolute logical channel such as `/api2`.
+   * @param handler - decoded endpoint handler returning the existing RPC result shape.
+   * @param options - channel trust policy.
+   * @returns asynchronous disposer removing the channel and its physical route.
+   */
+  handle(
+    channel: string,
+    handler: ConnectionRpcHandler,
+    options: ConnectionRpcHandlerOptions,
+  ): () => Promise<void>
+}
+
+/** Host `ctx.connection` shape consumed by transport-independent adapters. */
+export interface HostConnectionHandle {
+  /** Generic RPC channel registry. */
+  readonly rpc: HostConnectionRpc
+}
+
+/** Client caller for logical RPC channels carried by the current transport. */
+export interface ClientConnectionRpc {
+  /**
+   * Call one endpoint through an already registered logical channel.
+   * @param channel - absolute logical channel such as `/api2`.
+   * @param endpoint - channel-relative endpoint such as `goals/create`.
+   * @param payload - channel-owned request payload.
+   * @param signal - optional caller cancellation.
+   * @returns the existing RPC success/error result; correlation stays inside Connection.
+   */
+  call(
+    channel: string,
+    endpoint: string,
+    payload: unknown,
+    signal?: AbortSignal,
+  ): Promise<RpcResult<unknown>>
+}