Data rescue, not just schema tidying — the order matters:
1. Backfill companies.email from generalManagerEmail before the key is
stripped, or companies whose only address lived there stop receiving mail.
2. Backfill ownerName/Email/Phone (now required) from owner, GM, contact
person, then the columns; seed etradeManagerName so existing rows read as
matching rather than as a false mismatch.
3. Convert poaSameAsOwner: non-forwarders become poaDeclared='no' with their
poa* details cleared; forwarders become 'yes' and keep them, so they now
owe a DARS letter they were previously waived.
4. Derive poaDeclared for everyone else.
5. Move drafts off the deleted 'personnel' wizard step.
6. Drop the general_manager_* columns and strip gm*/poaSameAsOwner.
down() restores the column shape only; the stripped values are gone by design.
