disable server unless explicitly opted in (#7529)

packages/opencode/src/util/rpc.ts

@@ -13,11 +13,16 @@ export namespace Rpc {
     }
   }
 
+  export function emit(event: string, data: unknown) {
+    postMessage(JSON.stringify({ type: "rpc.event", event, data }))
+  }
+
   export function client<T extends Definition>(target: {
     postMessage: (data: string) => void | null
     onmessage: ((this: Worker, ev: MessageEvent<any>) => any) | null
   }) {
     const pending = new Map<number, (result: any) => void>()
+    const listeners = new Map<string, Set<(data: any) => void>>()
     let id = 0
     target.onmessage = async (evt) => {
       const parsed = JSON.parse(evt.data)
@@ -28,6 +33,14 @@ export namespace Rpc {
           pending.delete(parsed.id)
         }
       }
+      if (parsed.type === "rpc.event") {
+        const handlers = listeners.get(parsed.event)
+        if (handlers) {
+          for (const handler of handlers) {
+            handler(parsed.data)
+          }
+        }
+      }
     }
     return {
       call<Method extends keyof T>(method: Method, input: Parameters<T[Method]>[0]): Promise<ReturnType<T[Method]>> {
@@ -37,6 +50,17 @@ export namespace Rpc {
           target.postMessage(JSON.stringify({ type: "rpc.request", method, input, id: requestId }))
         })
       },
+      on<Data>(event: string, handler: (data: Data) => void) {
+        let handlers = listeners.get(event)
+        if (!handlers) {
+          handlers = new Set()
+          listeners.set(event, handlers)
+        }
+        handlers.add(handler)
+        return () => {
+          handlers!.delete(handler)
+        }
+      },
     }
   }
 }