Add SSL certificate provisioning button for superadmin

- New provision_ssl API endpoint runs certbot for new domains
- SSL button appears next to domain textarea for superadmin
- Shell script on server handles Apache config + Let's Encrypt
- DNS check skips domains without resolution to avoid certbot errors

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

index.html

@@ -1673,6 +1673,8 @@
                             <div class="form-group full-width">
                                 <label>Domainit (yksi per rivi)</label>
                                 <textarea id="company-edit-domains" rows="3" placeholder="intra.yritys.fi&#10;intra.toinen.fi" style="font-family:monospace;font-size:0.85rem;"></textarea>
+                                <button class="btn-secondary" id="btn-provision-ssl" style="display:none;margin-top:0.5rem;font-size:0.82rem;" title="Lisää domainit Apache-configiin ja päivitä Let's Encrypt -sertifikaatti">🔒 Päivitä SSL-sertifikaatti</button>
+                                <small id="ssl-provision-status" style="display:none;margin-top:0.25rem;color:#888;"></small>
                             </div>
                         </div>
                         <!-- Moduulit (vain superadmin) -->