fix: clean up GPU flags — hardware H.264 encoding not available on Win/Mac

AcceleratedVideoEncoder only enables VA-API encoding on Linux.
Windows/macOS hardware H.264 encoding in Chromium's WebRTC is not
reliably controllable — VP9 via libvpx remains the recommended codec.

packages/desktop/src/main.ts

@@ -522,6 +522,21 @@ function registerIpcHandlers(): void {
     // a safety net to prevent unhandled-message warnings
   });
 
+  // GPU feature status (debugging hardware encoding)
+  ipcMain.handle('get-gpu-info', async () => {
+    try {
+      const features = app.getGPUFeatureStatus();
+      const info: any = await app.getGPUInfo('complete');
+      return {
+        features,
+        gpu: info?.gpuDevice?.[0] ?? null,
+        videoEncode: (features as any)?.video_encode ?? 'unknown',
+      };
+    } catch {
+      return { features: {}, gpu: null, videoEncode: 'error' };
+    }
+  });
+
   // Auto-launch settings
   ipcMain.handle('get-auto-launch-settings', (): { openAtLogin: boolean; startMinimized: boolean } => {
     const saved = loadAutoLaunchSettings();
@@ -568,28 +583,45 @@ function initAutoUpdater(): void {
     autoUpdater.autoDownload = true;
     autoUpdater.autoInstallOnAppQuit = true;
 
+    // Track whether an update was confirmed to exist — only show error toast
+    // if the download fails after we know an update is available. Errors from
+    // the check itself (e.g. private repo, no releases, network) are silent.
+    let updateConfirmed = false;
+
     autoUpdater.on('update-available', (info: { version: string }) => {
+      updateConfirmed = true;
       mainWindow?.webContents.send('update-available', { version: info.version });
     });
 
+    autoUpdater.on('update-not-available', () => {
+      updateConfirmed = false;
+    });
+
     autoUpdater.on('update-downloaded', (info: { version: string }) => {
       mainWindow?.webContents.send('update-downloaded', { version: info.version });
     });
 
     autoUpdater.on('error', (err: Error) => {
-      mainWindow?.webContents.send('update-error', {
-        message: err.message,
-        releaseUrl: 'https://github.com/TheZwiss/backspace/releases/latest',
-      });
+      // Only notify renderer if we already confirmed an update exists but the
+      // download/install failed. Check-phase errors (auth, 404, network) are
+      // silently ignored — there's nothing actionable for the user.
+      if (updateConfirmed) {
+        mainWindow?.webContents.send('update-error', {
+          message: err.message,
+          releaseUrl: 'https://github.com/TheZwiss/backspace/releases/latest',
+        });
+      }
     });
 
     // Initial check with 10s delay
     setTimeout(() => {
+      updateConfirmed = false;
       autoUpdater.checkForUpdates().catch(() => {});
     }, 10_000);
 
     // Periodic check every 4 hours
     setInterval(() => {
+      updateConfirmed = false;
       autoUpdater.checkForUpdates().catch(() => {});
     }, 4 * 60 * 60 * 1000);
   } catch {
@@ -612,6 +644,16 @@ function handleDeepLink(url: string): void {
   }
 }
 
+// ─── GPU Acceleration ───────────────────────────────────────────────────────
+app.commandLine.appendSwitch('ignore-gpu-blocklist');
+app.commandLine.appendSwitch('enable-accelerated-video-decode');
+// Linux: enable VA-API hardware video encoding/decoding for WebRTC
+// (Windows/macOS hardware H.264 encoding is not reliably available in Electron's
+// Chromium WebRTC stack — VP9 via libvpx is the recommended codec for all platforms)
+if (process.platform === 'linux') {
+  app.commandLine.appendSwitch('enable-features', 'AcceleratedVideoEncoder,VaapiVideoEncoder,VaapiVideoDecoder');
+}
+
 // Electron 36+ defaults to GTK 4 on GNOME, which crashes if GTK 2/3
 // libraries are loaded in the same process. Force GTK 3 for compatibility.
 if (process.platform === 'linux') {
@@ -718,6 +760,15 @@ if (!gotTheLock) {
       ]));
     }
 
+    // Log GPU capabilities for debugging hardware encoding support
+    const gpuFeatures = app.getGPUFeatureStatus();
+    console.log('[GPU] Feature status:', JSON.stringify(gpuFeatures, null, 2));
+    app.getGPUInfo('complete').then((info: any) => {
+      console.log('[GPU] Active GPU:', info?.gpuDevice?.[0]?.driverVendor, info?.gpuDevice?.[0]?.driverVersion);
+      console.log('[GPU] Video encode:', info?.featureStatus?.video_encode ?? 'unknown');
+      console.log('[GPU] Video decode:', info?.featureStatus?.video_decode ?? 'unknown');
+    }).catch(() => {});
+
     // Purge ALL stale caches so Electron always loads fresh code on launch
     await session.defaultSession.clearStorageData({ storages: ['serviceworkers'] });
     await session.defaultSession.clearCache();