8d14441df4
Add a "Decline on behalf" action mirroring accept-on-behalf, for when a customer says no by phone/email. Flips a draft/sent/expired quote to declined, stamps declined_at, closes the public response window, and invalidates outstanding accept/decline tokens so the emailed link can't toggle it back. Optional free-text reason persisted to a new quotes.decline_reason column (migration 115) and shown on the quote detail page. Hard-delete intentionally not included.