test: poll terminal readiness in expectSingleOwningPty

Retry the terminal list assertion with polling to account for timing
delays in PTY state reporting from the runtime.

tests/e2e/helpers/startup-exec-readiness-oracle.ts

@@ -83,15 +83,24 @@ async function expectSingleOwningPty(
   terminal: string,
   ptyId: string
 ): Promise<void> {
-  const listed = await callStartupExecRuntime<RuntimeTerminalListResult>(page, 'terminal.list', {
-    worktree: `id:${worktreeId}`,
-    requireFreshPtyLiveness: true
-  })
-  expect(
-    listed.terminals
-      .filter((candidate) => candidate.tabId === tabId)
-      .map((candidate) => ({ handle: candidate.handle, ptyId: candidate.ptyId }))
-  ).toEqual([{ handle: terminal, ptyId }])
+  await expect
+    .poll(
+      async () => {
+        const listed = await callStartupExecRuntime<RuntimeTerminalListResult>(
+          page,
+          'terminal.list',
+          {
+            worktree: `id:${worktreeId}`,
+            requireFreshPtyLiveness: true
+          }
+        )
+        return listed.terminals
+          .filter((candidate) => candidate.tabId === tabId)
+          .map((candidate) => ({ handle: candidate.handle, ptyId: candidate.ptyId }))
+      },
+      { timeout: 30_000 }
+    )
+    .toEqual([{ handle: terminal, ptyId }])
 }
 
 export async function callStartupExecRuntime<TResult>(