E3: reap the recorded Chromium only after the daemon has exited

With the PID now recorded (E3), browse stop reaped Chromium while the
daemon was still shutting down; the daemon read that as a crash, exited 1
and left its state file (chromium-profile-isolation's headless stop test
failed 3/3 locally, passes on base). The CLI waits up to 5 s for the daemon
to exit before reaping a survivor.

browse/src/cli.ts

@@ -2080,7 +2080,12 @@ Refs:           After 'snapshot', use @e1, @e2... as selectors:
   // Playwright — but on macOS 26 the GPU process can survive that close and
   // spin at ~800% CPU forever. The state snapshot read above still carries
   // the launched child's identity; reap a verified survivor.
+  // Reap only after the daemon has finished its own shutdown: killing Chromium
+  // while the daemon is still closing reads as a crash, and the daemon exits(1)
+  // without removing its state file.
   if (command === 'stop') {
+    const deadline = Date.now() + 5_000;
+    while (Date.now() < deadline && isProcessAlive(state.pid)) await Bun.sleep(100);
     await reapRecordedChromium(state);
   }
 

browse/test/headless-gpu-and-reap.test.ts

@@ -254,10 +254,12 @@ describe('stop-reap wiring pins (#2709)', () => {
     );
 
     // 5. Post-graceful-stop: the daemon closed Chromium via Playwright, but a
-    //    surviving GPU process must still be reaped after sendCommand('stop').
+    //    surviving GPU process must still be reaped after sendCommand('stop') —
+    //    only once the daemon has exited (an earlier kill reads as a crash and
+    //    the daemon exits without removing its state file).
     const postStop = between('await sendCommand(state, command, commandArgs);', "if (command === 'focus')");
     expect(postStop).toMatch(
-      /if \(command === 'stop'\) \{\s*\n\s*await reapRecordedChromium\(state\);/,
+      /if \(command === 'stop'\) \{[\s\S]*while \(.*isProcessAlive\(state\.pid\)\)[^\n]*\n\s*await reapRecordedChromium\(state\);/,
     );
   });