fix: tolerate missing hosted system metrics

CHANGELOG.md

@@ -26,6 +26,7 @@ the frozen-backend fallback mirror it for their toolchains.
 - Every engine now has its own guide — 21 new pages under docs/engines plus an index covering all 16 TTS and 11 ASR engines, linked from both READMEs (#1556)
 
 ### Fixed
+- Hosted Studio no longer crashes when system information omits desktop-only RAM, CPU, or VRAM metrics
 - The crash-isolated ASR sidecar and its download preflight now agree on which model to load — setting the shared faster-whisper model variable applies to both variants instead of the sidecar quietly using a different one (#1556)
 - "Ready" now requires the deep health probe (a working database-backed route), not just the identity probe — a backend whose install broke underneath can no longer be announced up while every real request fails (#1548)
 - Supervisor restarts after repeat crashes now back off (immediate, then 5s, then 15s) instead of respawning back-to-back, so a tight crash loop can't burn the whole restart budget in seconds (#1548)

frontend/src/components/Header.jsx

@@ -155,6 +155,11 @@ export default function Header({
   // only re-renders the header chrome, not the whole App tree.
   const sysQuery = useSysinfo();
   const sysStats = sysQuery.data ?? null;
+  const hasRamStats =
+    Number.isFinite(sysStats?.ram) && Number.isFinite(sysStats?.total_ram);
+  const hasCpuStats = Number.isFinite(sysStats?.cpu);
+  const hasVramStats = Number.isFinite(sysStats?.vram);
+  const hasLiveStats = hasRamStats || hasCpuStats || hasVramStats;
   // Default OFF — chrome shouldn't double as a resource monitor. Power users
   // flip this on via Settings → Performance. Idle/Ready/Loading badge +
   // Flush button stay visible regardless (action-relevant).
@@ -327,16 +332,21 @@ export default function Header({
         />
         {sysStats && (
           <div className="flex items-center gap-[10px] [font-family:var(--chrome-font-mono)] text-[10.5px] text-[var(--chrome-fg-dim)] bg-transparent h-[var(--chrome-pill-h)] whitespace-nowrap shrink overflow-hidden tabular-nums slashed-zero max-[851px]:hidden!">
-            {showLiveStats && (
+            {showLiveStats && hasLiveStats && (
               <>
+                {hasRamStats && (
                   <span className="max-[1081px]:hidden">
                     <b className="text-[var(--chrome-fg-muted)] font-semibold">RAM</b>{' '}
                     {sysStats.ram.toFixed(1)}/{sysStats.total_ram.toFixed(0)}G
                   </span>
+                )}
+                {hasCpuStats && (
                   <span className="max-[1081px]:hidden">
                     <b className="text-[var(--chrome-fg-muted)] font-semibold">CPU</b>{' '}
                     {sysStats.cpu.toFixed(0)}%
                   </span>
+                )}
+                {hasVramStats && (
                   <span
                     className="[border-left:1px_solid_var(--chrome-border)] pl-[6px]"
                     aria-label={`VRAM usage: ${sysStats.vram.toFixed(1)} gigabytes`}
@@ -348,6 +358,7 @@ export default function Header({
                     </b>{' '}
                     {sysStats.vram.toFixed(1)}G
                   </span>
+                )}
               </>
             )}
             {/* Where the next job runs. Renders nothing until at least one

frontend/src/test/HeaderNavStyle.test.jsx

@@ -13,6 +13,8 @@ import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
 import React from 'react';
 
 import Header from '../components/Header';
+import { queryKeys } from '../api/hooks';
+import { useAppStore } from '../store';
 
 const windowActions = vi.hoisted(() => ({
   minimize: vi.fn(async () => {}),
@@ -24,11 +26,13 @@ vi.mock('@tauri-apps/api/window', () => ({ getCurrentWindow: () => windowActions
 
 afterEach(() => {
   delete window.__TAURI_INTERNALS__;
+  useAppStore.setState({ showHeaderLiveStats: false });
   vi.clearAllMocks();
 });
 
-function renderHeader(props) {
+function renderHeader(props, sysinfo) {
   const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+  if (sysinfo) qc.setQueryData(queryKeys.sysinfo, sysinfo);
   return render(
     <QueryClientProvider client={qc}>
       <Header mode="dub" setMode={() => {}} modelStatus="idle" {...props} />
@@ -37,6 +41,15 @@ function renderHeader(props) {
 }
 
 describe('Header — rail mode (default)', () => {
+  it('treats resource metrics as optional on hosted backends', () => {
+    useAppStore.setState({ showHeaderLiveStats: true });
+
+    expect(() => renderHeader({}, { platform: 'web' })).not.toThrow();
+    expect(screen.queryByText('RAM')).toBeNull();
+    expect(screen.queryByText('CPU')).toBeNull();
+    expect(screen.queryByText('VRAM')).toBeNull();
+  });
+
   it('keeps the breadcrumb and wordmark, and renders no tab strip', () => {
     const { container } = renderHeader({});
     expect(container.querySelector('.tabstrip')).toBeNull();

tests/test_changelog_style.py

@@ -39,6 +39,8 @@ _REF_REQUIRED_SECTIONS = {"Added", "Fixed"}
 # work with no issue or PR to point at). Match is by substring; keep this list
 # short and delete entries once they ship in a tagged release.
 _REF_ALLOWLIST = (
+    # owner-directed hosted Studio integration fix, no issue or PR
+    "Hosted Studio no longer crashes",
     # owner commit 7036e101 — first-run consent prompt, committed straight to main
     "First-run consent question for the existing opt-in analytics",
     # owner commits ce842737 + dc766baf — Colab notebook, committed straight to main