Quit with many shells: rare access violation (0xC0000005) under load

[Maxaubert]

Seen 2026-10-05 in the full e2e gate of PR #132: quitManyShells (ten shells, quit, three rounds) had rounds 2 and 3 exit with 0xC0000005 (an access violation), not 0. This was under load, since the full suite was running.

• Reruns: the scenario passed 3 of 3 times on its own, and a second full run passed all 46 scenarios.
• Likely not feat(core): agent states from Claude Code hooks, a Failed mark (#131) #132: its code paths are not touched in that scenario.
• Likely related to Closing the app with several shells can show node-pty's 'Assertion failed' dialog #127: the quit wait and node-pty 1.2.0-beta.15. Closing the app with several shells can show node-pty's 'Assertion failed' dialog #127 fixed the 0xC0000409 abort, so this may be a separate quit-time race in node-pty or Electron teardown.

Next step: if it shows up again, collect the WER dump (%LOCALAPPDATA%\CrashDumps\electron.exe.*.dmp) and read its stack with cdb, the way #127 was diagnosed.