fix: enable HLS cache by default

Disabling HLS caching makes live playback buffer and VOD seeking slower on Steam Deck. Keeping the performance cache enabled by default while bounding and clearing the cache preserves smooth playback without allowing cached media data to accumulate across sessions.

src/main/index.ts

@@ -13,14 +13,23 @@ log.transports.file.level = 'error'
 log.transports.console.level = 'debug'
 
 const isDev = !app.isPackaged
+const MAX_CACHE_BYTES = 512 * 1024 * 1024
 
 // Allows video.play() without a prior user gesture — play() is called from hls.js callbacks
 // that fire asynchronously long after the original click event.
 app.commandLine.appendSwitch('autoplay-policy', 'no-user-gesture-required')
 // Explicit cache size prevents Chromium's dynamic sizing, which causes "Invalid cache (current)
 // size" errors when available disk space fluctuates.
+app.commandLine.appendSwitch('disk-cache-size', String(MAX_CACHE_BYTES))
 
-app.commandLine.appendSwitch('disk-cache-size', String(500 * 1024 * 1024))
+async function clearDefaultSessionCache(reason: 'startup' | 'quit'): Promise<void> {
+  try {
+    await session.defaultSession.clearCache()
+    log.info(`[twitch4steamdeck] Cleared Electron cache on ${reason}.`)
+  } catch (err) {
+    log.warn(`[twitch4steamdeck] Failed to clear Electron cache on ${reason}.`, err)
+  }
+}
 
 function createWindow(): BrowserWindow {
   const isLinux = process.platform === 'linux'
@@ -105,6 +114,7 @@ function setupTwitchCors(): void {
 }
 
 app.whenReady().then(async () => {
+  await clearDefaultSessionCache('startup')
   setupTwitchCors()
   const clientId = import.meta.env.MAIN_VITE_TWITCH_CLIENT_ID ?? ''
   const auth = new AuthService(clientId)
@@ -119,10 +129,22 @@ app.whenReady().then(async () => {
   registerIpcHandlers(auth, helix, playback)
 
   const stopGamepad = startGamepadReader(() => BrowserWindow.getAllWindows()[0] ?? null)
+  let servicesStopped = false
+  let quitAfterCacheClear = false
 
-  app.on('before-quit', () => {
-    stopGamepad()
-    playback.stop()
+  app.on('before-quit', (event) => {
+    if (!servicesStopped) {
+      stopGamepad()
+      playback.stop()
+      servicesStopped = true
+    }
+    if (quitAfterCacheClear) return
+
+    event.preventDefault()
+    void clearDefaultSessionCache('quit').finally(() => {
+      quitAfterCacheClear = true
+      app.quit()
+    })
   })
 
   if (!clientId) {