Both branches of work added a migration with revision id 008 — the
threat-intel EUVD migration (008_add_euvd_fields, committed first) and
the multi-provider-auth migration (008_multi_provider_auth, committed
later). Alembic refused to start with 'Multiple head revisions are
present for given argument head'.
Resolution: multi-provider-auth becomes 009, chained after 008_add_euvd_fields.
No schema content changes; only revision/down_revision identifiers and
the filename.