test(app): fix isolated backend follow-ups (#20513)

packages/app/e2e/backend.ts

@@ -44,6 +44,14 @@ async function waitForHealth(url: string, probe = "/global/health") {
   throw new Error(`Timed out waiting for backend health at ${url}${probe}${last ? ` (${last})` : ""}`)
 }
 
+async function waitExit(proc: ReturnType<typeof spawn>, timeout = 10_000) {
+  if (proc.exitCode !== null) return
+  await Promise.race([
+    new Promise<void>((resolve) => proc.once("exit", () => resolve())),
+    new Promise<void>((resolve) => setTimeout(resolve, timeout)),
+  ])
+}
+
 const LOG_CAP = 100
 
 function cap(input: string[]) {
@@ -62,7 +70,6 @@ export async function startBackend(label: string): Promise<Handle> {
   const opencodeDir = path.join(repoDir, "packages", "opencode")
   const env = {
     ...process.env,
-    OPENCODE_DISABLE_SHARE: process.env.OPENCODE_DISABLE_SHARE ?? "true",
     OPENCODE_DISABLE_LSP_DOWNLOAD: "true",
     OPENCODE_DISABLE_DEFAULT_PLUGINS: "true",
     OPENCODE_EXPERIMENTAL_DISABLE_FILEWATCHER: "true",
@@ -117,7 +124,11 @@ export async function startBackend(label: string): Promise<Handle> {
     async stop() {
       if (proc.exitCode === null) {
         proc.kill("SIGTERM")
-        await new Promise((resolve) => proc.once("exit", () => resolve(undefined))).catch(() => undefined)
+        await waitExit(proc)
+      }
+      if (proc.exitCode === null) {
+        proc.kill("SIGKILL")
+        await waitExit(proc)
       }
       await fs.rm(sandbox, { recursive: true, force: true }).catch(() => undefined)
     },