perf(desktop): reduce CPU/GPU overhead in Tauri shell

- SSH monitor: adaptive polling 2s→10s after stabilization, cheap TCP
  probe before expensive SSH subprocess check
- SSH setup: exponential backoff in wait_for_master_ready and
  wait_local_forward_ready (250ms→2s cap)
- Health checks: exponential backoff (100ms→1s / 250ms→2s) instead of
  flat intervals
- Startup recovery poll: cap at 15 retries instead of infinite
- Remove webview log target in release builds (eliminates IPC overhead)
- Set global NO_PROXY env var at startup for all loopback addresses
- Remove reqwest::blocking feature; use raw TCP for sidecar shutdown and
  SSH health checks
- Disable pinch-to-zoom on macOS via WKWebView.setAllowsMagnification
- Add WebView2 browser args on Windows (proxy bypass + disable unused
  UI features)
- Add Cargo release profile: thin LTO, codegen-units=1, strip
- Extract apply_platform_window_config for consistent window setup
- Add vibrancy toggle in Appearance settings (macOS desktop only) with
  solid background fallback when disabled

packages/ui/src/App.tsx

@@ -277,6 +277,8 @@ function App({ apis }: AppProps) {
     if (providersCount > 0 && agentsCount > 0) return;
 
     let active = true;
+    let retries = 0;
+    const MAX_RETRIES = 15;
     const attempt = async () => {
       const state = useConfigStore.getState();
       if (state.providers.length > 0 && state.agents.length > 0) return;
@@ -287,7 +289,11 @@ function App({ apis }: AppProps) {
     };
 
     void attempt();
-    const id = setInterval(() => { if (active) void attempt(); }, 2000);
+    const id = setInterval(() => {
+      if (!active) return;
+      if (++retries >= MAX_RETRIES) { clearInterval(id); return; }
+      void attempt();
+    }, 2000);
     return () => { active = false; clearInterval(id); };
   }, [isConnected, isVSCodeRuntime, loadAgents, loadProviders, providersCount, agentsCount]);
 

packages/ui/src/components/sections/openchamber/OpenChamberVisualSettings.tsx

@@ -19,7 +19,7 @@ import {
     SelectTrigger,
     SelectValue,
 } from '@/components/ui/select';
-import { isDesktopShell, isVSCodeRuntime, isWebRuntime } from '@/lib/desktop';
+import { isDesktopShell, isVSCodeRuntime, isWebRuntime, desktopSetVibrancy } from '@/lib/desktop';
 import { useDeviceInfo } from '@/lib/device';
 import { usePwaDetection } from '@/hooks/usePwaDetection';
 import { updateDesktopSettings } from '@/lib/persistence';
@@ -209,6 +209,7 @@ export const OpenChamberVisualSettings: React.FC<OpenChamberVisualSettingsProps>
     } = useThemeSystem();
 
     const [themesReloading, setThemesReloading] = React.useState(false);
+    const [vibrancyEnabled, setVibrancyEnabled] = React.useState(true);
     const [chatRenderPreviewTick, setChatRenderPreviewTick] = React.useState(0);
     const reportUsage = useUIStore(state => state.reportUsage);
     const setReportUsage = useUIStore(state => state.setReportUsage);
@@ -219,6 +220,28 @@ export const OpenChamberVisualSettings: React.FC<OpenChamberVisualSettingsProps>
         void updateDesktopSettings({ reportUsage: enabled });
     }, [setReportUsage]);
 
+    const isMacDesktop = React.useMemo(() => {
+        if (!isDesktopShell()) return false;
+        if (typeof navigator === 'undefined') return false;
+        return /Macintosh|Mac OS X/.test(navigator.userAgent || '');
+    }, []);
+
+    React.useEffect(() => {
+        if (!isMacDesktop) return;
+        const stored = localStorage.getItem('desktopVibrancy');
+        if (stored !== null) {
+            setVibrancyEnabled(stored !== 'false');
+        }
+    }, [isMacDesktop]);
+
+    const handleVibrancyChange = React.useCallback((enabled: boolean) => {
+        setVibrancyEnabled(enabled);
+        localStorage.setItem('desktopVibrancy', String(enabled));
+        document.documentElement.classList.toggle('no-vibrancy', !enabled);
+        void desktopSetVibrancy(enabled);
+        void updateDesktopSettings({ desktopVibrancy: enabled });
+    }, []);
+
     const shouldAnimateChatPreview = isSettingsDialogOpen
         && (visibleSettings ? visibleSettings.includes('chatRenderMode') : true);
 
@@ -503,6 +526,24 @@ export const OpenChamberVisualSettings: React.FC<OpenChamberVisualSettingsProps>
                                 </Tooltip>
                             </div>
 
+                            {isMacDesktop && (
+                                <div className="flex items-center gap-2 py-1.5">
+                                    <Checkbox
+                                        checked={vibrancyEnabled}
+                                        onChange={handleVibrancyChange}
+                                        ariaLabel="Toggle window vibrancy"
+                                    />
+                                    <div className="flex min-w-0 flex-col">
+                                        <span className="typography-ui-label text-foreground">
+                                            Window vibrancy
+                                        </span>
+                                        <span className="typography-meta text-muted-foreground">
+                                            Translucent window background. Disabling may reduce energy usage.
+                                        </span>
+                                    </div>
+                                </div>
+                            )}
+
                             {showPwaInstallNameSetting && (
                                 <div className="py-1.5 space-y-1.5">
                                     <div className="flex min-w-0 flex-col">

packages/ui/src/lib/desktop.ts

@@ -147,6 +147,8 @@ export type DesktopSettings = {
   skillCatalogs?: SkillCatalogConfig[];
   // Opt-in to send anonymous usage reports for update checks (default: true)
   reportUsage?: boolean;
+  // macOS window vibrancy effect (default: true)
+  desktopVibrancy?: boolean;
 };
 
 type TauriGlobal = {
@@ -637,3 +639,18 @@ export const clearDesktopCache = async (): Promise<boolean> => {
     return false;
   }
 };
+
+export const desktopSetVibrancy = async (enabled: boolean): Promise<boolean> => {
+  if (!isTauriShell()) {
+    return false;
+  }
+
+  try {
+    const tauri = (window as unknown as { __TAURI__?: TauriGlobal }).__TAURI__;
+    await tauri?.core?.invoke?.('desktop_set_vibrancy', { enabled });
+    return true;
+  } catch (error) {
+    console.warn('Failed to set vibrancy', error);
+    return false;
+  }
+};

packages/ui/src/lib/device.ts

@@ -52,6 +52,10 @@ const setRootDeviceAttributes = (
 
   if (isTauriShellRuntime) {
     root.classList.add('desktop-runtime');
+    // Apply no-vibrancy class early so the first paint uses a solid background
+    // when vibrancy was previously disabled by the user.
+    const vibrancyOff = localStorage.getItem('desktopVibrancy') === 'false';
+    root.classList.toggle('no-vibrancy', vibrancyOff);
     root.style.setProperty('--is-mobile', '0');
     root.style.setProperty('--device-type', 'desktop');
     root.style.setProperty('--font-scale', '1');

packages/ui/src/lib/persistence.ts

@@ -82,6 +82,9 @@ const persistToLocalStorage = (settings: DesktopSettings) => {
       localStorage.removeItem('openchamber.pwaName');
     }
   }
+  if (typeof settings.desktopVibrancy === 'boolean') {
+    localStorage.setItem('desktopVibrancy', String(settings.desktopVibrancy));
+  }
 };
 
 type PersistApi = {

packages/ui/src/styles/design-system.css

@@ -135,12 +135,29 @@
     overscroll-behavior-y: none;
   }
 
-  :root.desktop-runtime body,
-  :root.desktop-runtime #root {
+  :root.desktop-runtime:not(.no-vibrancy) body,
+  :root.desktop-runtime:not(.no-vibrancy) #root {
     background: transparent !important;
     background-color: transparent !important;
   }
 
+  :root.desktop-runtime.no-vibrancy body,
+  :root.desktop-runtime.no-vibrancy #root {
+    background: var(--background) !important;
+    background-color: var(--background) !important;
+  }
+
+  /* When vibrancy is off, force sidebar overlays to solid and disable blur. */
+  :root.desktop-runtime.no-vibrancy {
+    --sidebar-overlay-strong: var(--sidebar) !important;
+    --sidebar-overlay-soft: var(--sidebar) !important;
+  }
+
+  :root.desktop-runtime.no-vibrancy .backdrop-blur {
+    -webkit-backdrop-filter: none !important;
+    backdrop-filter: none !important;
+  }
+
   .font-sans {
     font-family: var(--font-sans, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif) !important;
   }