Production deployment setup + feature complete

- Dockerfile + deploy.sh for Hetzner server
- Email verification via Better Auth + Resend
- Invite code flow (6-digit OTP, generate/join)
- Settlement share percent fix (payer vs debtor)
- OCR scanner fixes (date display, retry, viewfinder)
- app.json icon/splash/adaptive-icon configured
- iOS deployment target 15.5 (ML Kit requirement)
- DB migration 0014: household_invitations table

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/server/.env.example

@@ -0,0 +1,17 @@
+DATABASE_URL=postgresql://user:password@localhost:5432/haushaltsapp
+BETTER_AUTH_SECRET=
+BETTER_AUTH_URL=http://localhost:3000
+CORS_ORIGIN=http://localhost:3001
+STRIPE_SECRET_KEY=
+STRIPE_WEBHOOK_SECRET=
+NODE_ENV=development
+APPLE_CLIENT_ID=
+APPLE_TEAM_ID=
+APPLE_KEY_ID=
+APPLE_PRIVATE_KEY=
+MOBILE_APP_SCHEME=haushaltsapp://
+SMTP_HOST=localhost
+SMTP_PORT=1025
+SMTP_USER=
+SMTP_PASSWORD=
+SMTP_FROM=noreply@haushaltsapp.local