test(app): restore e2e playwright suite to green

- Fake gh stub now handles `gh pr view --json <fields>` by exiting 1
  with "no pull requests found for branch", matching the daemon's
  expected no-current-PR path; resolveCurrentPullRequestView no longer
  cascades failures across the suite.
- Rewrite the two post-setup script tests in workspace-setup-streaming
  to exercise explicit launch paths (UI scripts menu + daemon RPC) —
  39db3ea5 intentionally removed automatic post-setup script spawning.
- Harden terminal-alternate-screen synchronization: wait for the probe
  to observe alt-enter and alt-exit plus the final normal-screen marker
  before asserting, so the echoed command no longer races the alt-screen
  transition.

packages/app/e2e/terminal-alternate-screen.spec.ts

@@ -1,3 +1,4 @@
+import type { Page } from "@playwright/test";
 import { test, expect } from "./fixtures";
 import { TerminalE2EHarness, withTerminalInApp } from "./helpers/terminal-dsl";
 import {
@@ -10,6 +11,47 @@ import {
 } from "./helpers/terminal-probes";
 import { waitForTerminalContent } from "./helpers/terminal-perf";
 
+async function waitForAlternateScreenExit(page: Page, afterAlt: string, timeout: number) {
+  let lastText = "";
+  let lastProbe = await readTerminalRenderProbe(page);
+
+  try {
+    await expect
+      .poll(
+        async () => {
+          lastText = await terminalVisibleText(page);
+          lastProbe = await readTerminalRenderProbe(page);
+          return (
+            lastProbe.altEnterWrites > 0 &&
+            lastProbe.altExitWrites > 0 &&
+            lastText.includes(afterAlt)
+          );
+        },
+        {
+          intervals: [50],
+          message: `wait for alternate-screen exit and ${afterAlt} output`,
+          timeout,
+        },
+      )
+      .toBe(true);
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    throw new Error(
+      `Timed out waiting for alternate-screen exit: ${message}\n${JSON.stringify(
+        {
+          afterAlt,
+          probe: summarizeTerminalRenderProbe(lastProbe),
+          visibleTextTail: lastText.slice(-500),
+        },
+        null,
+        2,
+      )}`,
+    );
+  }
+
+  return lastProbe;
+}
+
 test.describe("Terminal alternate-screen transitions", () => {
   let harness: TerminalE2EHarness;
 
@@ -53,9 +95,7 @@ test.describe("Terminal alternate-screen transitions", () => {
         `printf '\\033[?1049h\\033[2J\\033[HALT_SCREEN_TOP\\n'; sleep 0.25; printf '\\033[?1049l'; echo ${afterAlt}\n`,
         { delay: 0 },
       );
-      await waitForTerminalContent(page, (text) => text.includes(afterAlt), 10_000);
-      await page.waitForTimeout(250);
-      const probe = await readTerminalRenderProbe(page);
+      const probe = await waitForAlternateScreenExit(page, afterAlt, 10_000);
       const probeSummary = summarizeTerminalRenderProbe(probe);
 
       await testInfo.attach("alternate-screen-probe", {