Dashboard: surface fleet load errors instead of infinite skeletons (0.38.1)

The cockpit cards gated purely on `fleet.data`, so any failed
/api/dashboard/fleet request (e.g. a stale backend returning 404, or a
500) left the new components stuck on skeletons forever. Render a clear
error banner with the API message and a Retry button when the query
errors with no data, so the actual cause is visible.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/version.py

@@ -1,3 +1,3 @@
 """Single source of truth for the StackPilot release version."""
 
-APP_VERSION = "0.38.0"
+APP_VERSION = "0.38.1"

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "stackpilot-frontend",
   "private": true,
-  "version": "0.38.0",
+  "version": "0.38.1",
   "type": "module",
   "scripts": {
     "dev": "vite",

frontend/src/pages/Dashboard.tsx

@@ -1,6 +1,6 @@
 import { useState } from "react";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
-import { Clock, RefreshCw } from "lucide-react";
+import { AlertTriangle, Clock, RefreshCw } from "lucide-react";
 import { toast } from "sonner";
 import { Card } from "@/components/ui";
 import { HostHeader } from "@/components/hosts/HostHeader";
@@ -66,33 +66,51 @@ export function Dashboard() {
         </button>
       </div>
 
-      {/* ---- Needs attention ---- */}
-      <AttentionStrip items={fleet.data?.attention} loading={fleet.isLoading} />
-
-      {/* ---- Fleet KPIs ---- */}
-      {fleet.data ? (
-        <FleetKpiRow kpis={fleet.data.kpis} />
-      ) : (
-        <div className="grid grid-cols-2 gap-3 sm:grid-cols-3 lg:grid-cols-6">
-          {Array.from({ length: 6 }).map((_, i) => (
-            <div key={i} className="sp-skeleton h-24" />
-          ))}
+      {/* ---- Fleet cockpit (attention + KPIs + status + hosts) ---- */}
+      {fleet.isError && !fleet.data ? (
+        <div className="flex items-center justify-between gap-3 rounded-card border border-red-300 bg-red-50 px-4 py-3 text-sm text-red-700 dark:border-red-900/50 dark:bg-red-900/20 dark:text-red-300">
+          <span className="flex items-center gap-2">
+            <AlertTriangle className="h-5 w-5 shrink-0" />
+            Couldn’t load fleet overview: {apiErrorMessage(fleet.error)}
+          </span>
+          <button
+            onClick={refreshFleet}
+            className="shrink-0 rounded-pill border border-red-300 px-3 py-1 text-xs font-medium hover:bg-red-100 dark:border-red-800 dark:hover:bg-red-900/40"
+          >
+            Retry
+          </button>
         </div>
-      )}
+      ) : (
+        <>
+          {/* Needs attention */}
+          <AttentionStrip items={fleet.data?.attention} loading={fleet.isLoading} />
 
-      {/* ---- Status + hosts ---- */}
-      <div className="grid grid-cols-1 gap-4 lg:grid-cols-[340px_1fr]">
-        {fleet.data ? (
-          <StackStatusBar totals={fleet.data.status_totals} unhealthy={fleet.data.kpis.unhealthy} />
-        ) : (
-          <div className="sp-skeleton h-40" />
-        )}
-        {fleet.data ? (
-          <HostResourceTable hosts={fleet.data.hosts} />
-        ) : (
-          <div className="sp-skeleton h-40" />
-        )}
-      </div>
+          {/* Fleet KPIs */}
+          {fleet.data ? (
+            <FleetKpiRow kpis={fleet.data.kpis} />
+          ) : (
+            <div className="grid grid-cols-2 gap-3 sm:grid-cols-3 lg:grid-cols-6">
+              {Array.from({ length: 6 }).map((_, i) => (
+                <div key={i} className="sp-skeleton h-24" />
+              ))}
+            </div>
+          )}
+
+          {/* Status + hosts */}
+          <div className="grid grid-cols-1 gap-4 lg:grid-cols-[340px_1fr]">
+            {fleet.data ? (
+              <StackStatusBar totals={fleet.data.status_totals} unhealthy={fleet.data.kpis.unhealthy} />
+            ) : (
+              <div className="sp-skeleton h-40" />
+            )}
+            {fleet.data ? (
+              <HostResourceTable hosts={fleet.data.hosts} />
+            ) : (
+              <div className="sp-skeleton h-40" />
+            )}
+          </div>
+        </>
+      )}
 
       {/* ---- Local host stacks ---- */}
       <section>