Add notification preferences and alternate dues payment options

Notification preferences (migration 048):
- Per-member opt-out of muteable categories (bookings, classes, forms,
  admin alerts); billing is always-on. Opt-out model, default on.
- Dispatcher reads prefs and marks muted outbox rows 'skipped' instead
  of sending; pure isMuted logic, fail-open on a prefs lookup error.
- notification_preferences table (default-deny RLS); /me toggles and
  self-view via validated service-client actions.

Alternate dues payment methods (migration 049):
- Admin sets external pay-here URLs per platform (PayPal/Zeffy/Venmo)
  in /settings; members see active ones on /me and pay off-platform;
  the treasurer reconciles manually (platform pre-tagged). https-only.
- dues_payment_methods table (SELECT space member, write admin/board).

/me visual pass:
- Restore the chip/preset profile editor (skills/interests/willing-to/
  affiliations); promote ChipInput and presets to shared modules.
- Gate the Stripe pay-dues button on whether the space has Stripe
  configured; show external links or a contact-admin note otherwise.

app/(app)/profile/affiliations-form.tsx

@@ -3,7 +3,7 @@
 import { useState, useTransition } from 'react'
 import { useRouter } from 'next/navigation'
 import { discloseAffiliations } from '@/lib/actions'
-import { ChipInput } from './chip-input'
+import { ChipInput } from '@/components/chip-input'
 
 export function AffiliationsForm({ initial }: { initial: { affiliations: string[] } }) {
   const router = useRouter()