A scoring error no longer skips setup detection for the ticker: the
rollback already restores a clean transaction, and qualification
re-gates on live scores at alert time, so a stale score is recoverable
but a skipped scan is not.
Iterating symbol strings instead of Ticker instances fixes a latent
crash the new regression test caught: rollback() expires ORM objects
regardless of expire_on_commit, so touching ticker.symbol in the except
handler triggered sync lazy-loading, which raises on an AsyncSession
and killed the whole scan on the first per-ticker error.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>