fix(server): keep instance timeout alive

Replace AbortSignal.timeout with a managed AbortController timer so a stuck loopback request keeps the Node event loop alive until it is aborted. Preserve caller-provided signals and clear the timer when fetch settles.

Validated with the instance-client timeout test and server typecheck; the full server suite passes except for the known local branch-name fixture.

Author: pascalandr

packages/server/src/workspaces/instance-client.ts

@@ -53,11 +53,14 @@ export function createInstanceClient(
   return createOpencodeClient({
     baseUrl: `http://${LOOPBACK_HOST}:${port}/`,
     headers,
-    fetch: (url, init) =>
-      fetch(url, {
-        ...(init as RequestInit),
-        signal: (init as RequestInit)?.signal ?? AbortSignal.timeout(timeoutMs),
-      }),
+    fetch: (url, init) => {
+      const requestInit = init as RequestInit
+      if (requestInit?.signal) return fetch(url, requestInit)
+
+      const controller = new AbortController()
+      const timeout = setTimeout(() => controller.abort(new DOMException("Request timed out", "TimeoutError")), timeoutMs)
+      return fetch(url, { ...requestInit, signal: controller.signal }).finally(() => clearTimeout(timeout))
+    },
     ...(directory ? { directory } : {}),
   })
 }