[P2] Waitlist management

[KalebCole]

Priority: P2 (Medium) Manage event waitlist - promote guests, notify when spots open. ## Use Cases - See who is on the waitlist - Manually promote someone from waitlist - Auto-notify waitlisted guests when spots open - Reorder waitlist priority ## Proposed Commands bash # View waitlist partiful waitlist <eventId> # Promote specific person partiful waitlist <eventId> --promote "+12065551234" # Promote next N people partiful waitlist <eventId> --promote-next 3 # Notify waitlist that spots opened partiful waitlist <eventId> --notify "2 spots just opened!" ## Output Waitlist: Game Night (5 people) =============================== 1. John Doe (+1206555...) - joined 2d ago 2. Jane Smith (+1206555...) - joined 1d ago 3. Bob Wilson (+1206555...) - joined 12h ago ## Acceptance Criteria - [ ] View waitlist with position - [ ] Promote individual from waitlist - [ ] Bulk promote next N - [ ] Notify waitlisted guests