dashboard: show GATEWAY_HEALTH_URL instead of PID for remote gateways

When the dashboard connects to a remote gateway via GATEWAY_HEALTH_URL,
display the URL instead of the remote PID (which is meaningless locally).
Falls back to PID display for local gateways as before.

- Backend: expose gateway_health_url in /api/status response
- Frontend: prefer gateway_health_url over PID in gatewayValue()
- Add truncate + title tooltip for long URLs that overflow the card
- Add min-w-0/overflow-hidden on status cards for proper truncation
- Tests: verify gateway_health_url in remote and no-URL scenarios

web/src/lib/api.ts

@@ -213,6 +213,7 @@ export interface StatusResponse {
   config_version: number;
   env_path: string;
   gateway_exit_reason: string | null;
+  gateway_health_url: string | null;
   gateway_pid: number | null;
   gateway_platforms: Record<string, PlatformStatus>;
   gateway_running: boolean;

web/src/pages/StatusPage.tsx

@@ -53,6 +53,7 @@ export default function StatusPage() {
   };
 
   function gatewayValue(): string {
+    if (status!.gateway_running && status!.gateway_health_url) return status!.gateway_health_url;
     if (status!.gateway_running && status!.gateway_pid) return `${t.status.pid} ${status!.gateway_pid}`;
     if (status!.gateway_running) return t.status.runningRemote;
     if (status!.gateway_state === "startup_failed") return t.status.startFailed;
@@ -137,14 +138,14 @@ export default function StatusPage() {
 
       <div className="grid gap-4 sm:grid-cols-3">
         {items.map(({ icon: Icon, label, value, badgeText, badgeVariant }) => (
-          <Card key={label}>
+          <Card key={label} className="min-w-0 overflow-hidden">
             <CardHeader className="flex flex-row items-center justify-between pb-2">
               <CardTitle className="text-sm font-medium">{label}</CardTitle>
               <Icon className="h-4 w-4 text-muted-foreground" />
             </CardHeader>
 
             <CardContent>
-              <div className="text-2xl font-bold font-display">{value}</div>
+              <div className="text-2xl font-bold font-display truncate" title={value}>{value}</div>
 
               {badgeText && (
                 <Badge variant={badgeVariant} className="mt-2">