feat: unify logging via electron-log and add IPC error boundary

Bug reports from Steam Deck (Flatpak) arrived without any useful context:
no terminal, no log file, no trace of what failed. Silent catches in
helixClient hid quota and token errors entirely. IPC handler exceptions
reached the renderer as rejected promises with no server-side record.

electron-log now writes to a rotating log file (~1 MB, 5 files) that
users can attach to bug reports. All IPC handlers are wrapped in
safeHandle, which logs and re-throws at the boundary. Optional-feature
failures (chapters, profile images, viewer counts) emit log.warn with
enough context to diagnose. A React ErrorBoundary catches render crashes
app-wide and logs them before showing a reload prompt.

src/main/index.ts

@@ -6,6 +6,11 @@ import { PlaybackService } from './playback/playbackService'
 import { registerIpcHandlers } from './ipc/handlers'
 import { startGamepadReader } from './input/gamepadReader'
 import { getHlsCacheEnabled } from './prefs/hlsCachePref'
+import log from 'electron-log/main'
+
+log.initialize()
+log.transports.file.level = 'info'
+log.transports.console.level = 'debug'
 
 const isDev = !app.isPackaged
 
@@ -130,9 +135,7 @@ app.whenReady().then(async () => {
   })
 
   if (!clientId) {
-    console.warn(
-      '[twitch4steamdeck] MAIN_VITE_TWITCH_CLIENT_ID nicht gesetzt — Login wird im UI als nicht konfiguriert angezeigt.'
-    )
+    log.warn('[twitch4steamdeck] MAIN_VITE_TWITCH_CLIENT_ID nicht gesetzt — Login wird im UI als nicht konfiguriert angezeigt.')
   }
 
   createWindow()