Hostinger Reach integration UI + ARC Buildium matching, drop Mailchimp

- HostingerReachPage (replaces MailchimpPage): connect Reach via
  reach-connection, per-association segment sync via reach-sync
- ARC Applications: Buildium import review/matching updates
- buildium-import-stage/apply: latest staging + apply changes (already
  deployed to Supabase)
- migrations: hostinger_reach_integration + arc_finalized_lock service
  role (already applied to live DB)
- CI: note that deployment is VPS-side polling (auto-deploy.sh cron)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/SettingsSidebar.tsx

@@ -50,7 +50,7 @@ export const SETTINGS_PAGES = [
     items: [
       { path: "/dashboard/settings/buildium", title: "Buildium", icon: Building2 },
       { path: "/dashboard/settings/stripe-accounts", title: "Payment Gateways", icon: CreditCard },
-      { path: "/dashboard/mailchimp", title: "Mailchimp", icon: Mail },
+      { path: "/dashboard/hostinger-reach", title: "Hostinger Reach", icon: Mail },
     ],
   },
 ];