Fix S3/SMTP connectivity and add one-click invite flow

- Fix MinIO port parsing bug: use protocol-appropriate defaults (443/80)
  instead of hardcoded 9000 fallback, enabling public URL endpoint
- Remove unused SMTP server config from NextAuth EmailProvider to prevent
  connection errors (sendVerificationRequest is fully overridden)
- Replace extra_hosts with DNS config (8.8.8.8) so container resolves
  mail.monaco-opc.com to public IP instead of host loopback
- Add invite token auth: single-click accept-invite flow replacing broken
  two-email invitation process
- Auto-send invitation emails on bulk user creation
- Update email template expiry text from 24 hours to 7 days

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

prisma/schema.prisma

@@ -236,6 +236,10 @@ model User {
   passwordSetAt            DateTime? // When password was set
   mustSetPassword          Boolean   @default(true) // Force setup on first login
 
+  // Invitation token for one-click invite acceptance
+  inviteToken              String?   @unique
+  inviteTokenExpiresAt     DateTime?
+
   createdAt     DateTime     @default(now())
   updatedAt     DateTime     @updatedAt
   lastLoginAt   DateTime?