ci-poller subshell continue fallthrough

Trap: wrapping each CI-poller iteration in a subshell looks ideal for per-issue EXIT cleanup, but continue is no longer inside the enclosing while; Bash errors, then later commands can edit with invalid data. Fix: use exit 0 for intentional per-issue skips inside the subshell, and reserve continue for the outer loop. Keep the per-issue trap and regression-test that every resolver/decode failure skips gh issue edit.