feat(member): account/profile polish + tier upgrade flow

- Timezone: curated USelectMenu dropdown (app/config/timezones.js), preserves unknown saved values
- Profile save now uses useToast() for success/error; remove inline save banner
- Nav onboarding dot nudged down 1px for optical alignment with lowercase text
- Onboarding: skip a suggestion with POST /api/onboarding/track {skip}; member.onboarding.skipped map; does not affect graduation
- CirclePicker takes :saved-value so 'Current' badge stays until save completes
- PrivacyToggle is binary (USwitch labeled Private); member schema enum reduced to ['members','private']; zod coerces legacy 'public'
- New /member/payment-setup page: HelcimPay $0 verify + update-contribution, wired from account.vue via requiresPaymentSetup redirect
- Helcim portal: NUXT_PUBLIC_HELCIM_PORTAL_URL env + account.vue 'Manage billing in Helcim' link
- Migration script: scripts/migrate-privacy-public-to-members.js

tests/server/api/validation.test.js

@@ -180,9 +180,15 @@ describe('memberProfileUpdateSchema', () => {
     expect(result.success).toBe(false)
   })
 
-  it('accepts valid privacy values', () => {
+  it('accepts valid binary privacy values', () => {
+    expect(memberProfileUpdateSchema.safeParse({ bioPrivacy: 'members' }).success).toBe(true)
+    expect(memberProfileUpdateSchema.safeParse({ bioPrivacy: 'private' }).success).toBe(true)
+  })
+
+  it('coerces legacy "public" privacy value to "members"', () => {
     const result = memberProfileUpdateSchema.safeParse({ bioPrivacy: 'public' })
     expect(result.success).toBe(true)
+    expect(result.data.bioPrivacy).toBe('members')
   })
 })