fix: update SSL certificate selection options and descriptions for clarity

frontend/src/components/ProxyHostForm.tsx

@@ -580,22 +580,23 @@ export default function ProxyHostForm({ host, onSubmit, onCancel }: ProxyHostFor
           {/* SSL Certificate Selection */}
           <div>
             <label className="block text-sm font-medium text-gray-300 mb-2">
-              SSL Certificate (Custom Only)
+              SSL Certificate
             </label>
             <select
               value={formData.certificate_id || 0}
               onChange={e => setFormData({ ...formData, certificate_id: parseInt(e.target.value) || null })}
               className="w-full bg-gray-900 border border-gray-700 rounded-lg px-4 py-2 text-white focus:outline-none focus:ring-2 focus:ring-blue-500"
             >
-              <option value={0}>Request a new SSL Certificate (Let's Encrypt)</option>
-              {certificates.filter(c => c.provider === 'custom').map(cert => (
-                <option key={cert.id} value={cert.id}>
-                  {cert.name} (Custom)
+              <option value={0}>Auto-manage with Let's Encrypt (recommended)</option>
+              {certificates.map(cert => (
+                <option key={cert.id || cert.domain} value={cert.id ?? 0}>
+                  {(cert.name || cert.domain)}
+                  {cert.provider ? ` (${cert.provider})` : ''}
                 </option>
               ))}
             </select>
             <p className="text-xs text-gray-500 mt-1">
-              Let's Encrypt certificates are managed automatically. Use custom certificates for self-signed or other providers.
+              Choose an existing certificate if already issued for these domains, or let Charon request/renew via Let's Encrypt automatically.
             </p>
           </div>