fix(server): managed Codex conversations recover after ChatGPT token renewal#16849

fix(server): restart stale Codex sessions despite background activity

refactor(server): simplify managed Codex renewal checks

test(server): cover managed Codex renewal through auth and shared sessions

Merge origin/main into fix/managed-codex-token-renewal

fix(server): replace a stale Codex session even with background work pending

fix(server): managed Codex conversations recover after ChatGPT token renewal