Historical notes migration (addendum §9.2)

One-time, pre-go-live step. Scans the Contacts export's Notes column (and, optionally, the Open Quotes export's Notes column) for the base spec §4 rules 6/7 keyword sets and proposes opt-outs — nothing is written until a rep reviews the list below and ticks which ones to commit. Conservative direction only: when in doubt, leave it unticked and handle manually.