Dashboard: editable gateway settings + public-exposure panel

Surfaces the DNS/Cloudflare/public state that previously required editing
castle.yaml + curl:

- API: GET /gateway now returns domain, public_domain, tunnel_id,
  tunnel_connected, and a public_url per public route; new PUT /gateway/config
  edits tls/domain/public_domain/tunnel_id in castle.yaml (deploy to apply).
  save_config now persists public_domain/tunnel_id (previously dropped).
- UI: a GatewaySettings row in the Gateway panel shows TLS / domain / public
  (tunnel up/down + public_domain) with inline edit; each public route gets a
  green "public" badge linking to its <name>.<public_domain> URL.

app/src/components/GatewayPanel.tsx

@@ -1,10 +1,11 @@
 import { useMemo, useState } from "react"
 import { Link } from "react-router-dom"
-import { Globe, RefreshCw, FileText, ExternalLink } from "lucide-react"
+import { Globe, RefreshCw, FileText, ExternalLink, Cable } from "lucide-react"
 import type { GatewayInfo, HealthStatus } from "@/types"
 import { useGatewayReload, useCaddyfile } from "@/services/api/hooks"
 import { subdomainUrl } from "@/lib/labels"
 import { HealthBadge } from "./HealthBadge"
+import { GatewaySettings } from "./GatewaySettings"
 
 interface GatewayPanelProps {
   gateway: GatewayInfo
@@ -58,6 +59,9 @@ export function GatewayPanel({ gateway, statuses }: GatewayPanelProps) {
         </div>
       </div>
 
+      {/* Routing + public-exposure settings (editable) */}
+      <GatewaySettings gateway={gateway} />
+
       {/* Route table — every gateway route, of every kind */}
       {gateway.routes.length > 0 && (
         <table className="w-full text-sm">
@@ -98,6 +102,17 @@ export function GatewayPanel({ gateway, statuses }: GatewayPanelProps) {
                     ) : (
                       route.address
                     )}
+                    {route.public_url && (
+                      <a
+                        href={route.public_url}
+                        target="_blank"
+                        rel="noopener noreferrer"
+                        title={route.public_url}
+                        className="ml-2 inline-flex items-center gap-1 text-[0.65rem] px-1.5 py-0.5 rounded bg-green-500/15 text-green-500 hover:bg-green-500/25"
+                      >
+                        <Cable size={10} /> public
+                      </a>
+                    )}
                   </td>
                   <td className="px-4 py-2">
                     <KindBadge kind={route.kind} />