refactor: extract IPC channel names into a single source of truth

Duplicate raw string literals across handlers.ts, preload/index.ts made
typos undetectable at compile time and renames a multi-file grep problem.
A single channels.ts now owns all channel names; both files import from it.

Also fixes two bugs found during testing:
- LoginScreen and AccountScreen buttons were not triggerable via gamepad
  A-button: synthetic KeyboardEvents are untrusted and don't fire native
  button clicks. Added explicit keydown handlers that call the action directly.
- AppShell loading overlay could disappear while hlsPayload was still null
  if the playback:event 'started' IPC message arrived before playback:hls-url.
  Overlay now stays visible until hlsPayload is set, regardless of playState.

src/main/ipc/channels.ts

@@ -0,0 +1,36 @@
+export const IPC = {
+  appQuit: 'app:quit',
+  authStatus: 'auth:get-status',
+  authStart: 'auth:start-device-flow',
+  authCancel: 'auth:cancel',
+  authLogout: 'auth:logout',
+  authConfigured: 'auth:is-configured',
+  /** main → renderer */
+  authEvent: 'auth:event',
+
+  twitchGetFollowed: 'twitch:get-followed',
+  twitchGetOwnUser: 'twitch:get-own-user',
+  twitchGetVideos: 'twitch:get-videos',
+  twitchGetTopGames: 'twitch:get-top-games',
+  twitchGetTopStreams: 'twitch:get-top-streams',
+  twitchGetVodChapters: 'twitch:get-vod-chapters',
+  historyGetProgress: 'history:get-progress',
+
+  playbackStartLive: 'playback:start-live',
+  playbackStartVod: 'playback:start-vod',
+  playbackStop: 'playback:stop',
+  playbackPause: 'playback:pause',
+  playbackReportPosition: 'playback:report-position',
+  playbackGetQualities: 'playback:get-qualities',
+  /** main → renderer */
+  playbackEvent: 'playback:event',
+  /** main → renderer: HLS-URL + Metadaten für den Renderer-seitigen Video-Player */
+  playbackHlsUrl: 'playback:hls-url',
+
+  appGetCacheSize: 'app:get-cache-size',
+  appClearCache: 'app:clear-cache',
+  appSetHlsCacheEnabled: 'app:set-hls-cache-enabled',
+
+  /** main → renderer */
+  gamepadInput: 'gamepad-input'
+} as const

src/main/ipc/handlers.ts

@@ -8,40 +8,9 @@ import type { PlaybackService } from '../playback/playbackService'
 import type { HlsUrlPayload } from '../playback/playbackService'
 import type { PlaybackEvent } from '../playback/types'
 import { getProgressMap } from '../store/historyRepo'
+import { IPC } from './channels'
 
-export const IPC = {
-  appQuit: 'app:quit',
-  authStatus: 'auth:get-status',
-  authStart: 'auth:start-device-flow',
-  authCancel: 'auth:cancel',
-  authLogout: 'auth:logout',
-  authConfigured: 'auth:is-configured',
-  /** main → renderer */
-  authEvent: 'auth:event',
-
-  twitchGetFollowed: 'twitch:get-followed',
-  twitchGetOwnUser: 'twitch:get-own-user',
-  twitchGetVideos: 'twitch:get-videos',
-  twitchGetTopGames: 'twitch:get-top-games',
-  twitchGetTopStreams: 'twitch:get-top-streams',
-  twitchGetVodChapters: 'twitch:get-vod-chapters',
-  historyGetProgress: 'history:get-progress',
-
-  playbackStartLive: 'playback:start-live',
-  playbackStartVod: 'playback:start-vod',
-  playbackStop: 'playback:stop',
-  playbackPause: 'playback:pause',
-  playbackReportPosition: 'playback:report-position',
-  playbackGetQualities: 'playback:get-qualities',
-  /** main → renderer */
-  playbackEvent: 'playback:event',
-  /** main → renderer: HLS-URL + Metadaten für den Renderer-seitigen Video-Player */
-  playbackHlsUrl: 'playback:hls-url',
-
-  appGetCacheSize: 'app:get-cache-size',
-  appClearCache: 'app:clear-cache',
-  appSetHlsCacheEnabled: 'app:set-hls-cache-enabled'
-} as const
+export { IPC }
 
 export function registerIpcHandlers(
   auth: AuthService,

src/preload/index.ts

@@ -1,37 +1,5 @@
 import { contextBridge, ipcRenderer, type IpcRendererEvent } from 'electron'
-
-const IPC = {
-  appQuit: 'app:quit',
-  authStatus: 'auth:get-status',
-  authStart: 'auth:start-device-flow',
-  authCancel: 'auth:cancel',
-  authLogout: 'auth:logout',
-  authConfigured: 'auth:is-configured',
-  authEvent: 'auth:event',
-
-  twitchGetFollowed: 'twitch:get-followed',
-  twitchGetOwnUser: 'twitch:get-own-user',
-  twitchGetVideos: 'twitch:get-videos',
-  twitchGetTopGames: 'twitch:get-top-games',
-  twitchGetTopStreams: 'twitch:get-top-streams',
-  twitchGetVodChapters: 'twitch:get-vod-chapters',
-  historyGetProgress: 'history:get-progress',
-
-  playbackStartLive: 'playback:start-live',
-  playbackStartVod: 'playback:start-vod',
-  playbackStop: 'playback:stop',
-  playbackPause: 'playback:pause',
-  playbackReportPosition: 'playback:report-position',
-  playbackGetQualities: 'playback:get-qualities',
-  playbackEvent: 'playback:event',
-  playbackHlsUrl: 'playback:hls-url',
-
-  appGetCacheSize: 'app:get-cache-size',
-  appClearCache: 'app:clear-cache',
-  appSetHlsCacheEnabled: 'app:set-hls-cache-enabled',
-
-  gamepadInput: 'gamepad-input'
-} as const
+import { IPC } from '../main/ipc/channels'
 
 export type AuthStatus = 'logged-out' | 'logged-in'
 

src/renderer/src/screens/AccountScreen.tsx

@@ -50,6 +50,8 @@ export default function AccountScreen({ hasFocus, onRequestSidebar, onLogout }:
       if (e.key === 'ArrowLeft') {
         e.preventDefault()
         onRequestSidebar()
+      } else if (e.key === 'Enter') {
+        void handleLogout()
       }
     }
     window.addEventListener('keydown', onKey)

src/renderer/src/screens/AppShell.tsx

@@ -307,7 +307,7 @@ export default function AppShell({ onLogout }: Props): JSX.Element {
       {isGlobalPlaying && !selectedChannel && (
         <>
           {/* Lade-Overlay während streamlink läuft */}
-          {livePlayState === 'starting' && !liveHlsPayload && (
+          {!liveHlsPayload && livePlayState !== 'error' && (
             <div style={{
               position: 'fixed', inset: 0, zIndex: 100,
               background: '#000', display: 'flex',

src/renderer/src/screens/LoginScreen.tsx

@@ -25,6 +25,16 @@ export default function LoginScreen({ onAuthorized }: Props): JSX.Element {
     startBtnRef.current?.focus()
   }, [])
 
+  useEffect(() => {
+    const onKey = (e: KeyboardEvent): void => {
+      if (e.key !== 'Enter') return
+      if (phase.kind === 'idle' || phase.kind === 'error') void start()
+      else if (phase.kind === 'awaiting') void cancel()
+    }
+    window.addEventListener('keydown', onKey)
+    return () => window.removeEventListener('keydown', onKey)
+  }, [phase])
+
   // Auth-Events aus Main abonnieren.
   useEffect(() => {
     const off = window.t4sd.auth.onEvent((event) => {

src/renderer/src/types/t4sd.d.ts

@@ -1,4 +1,5 @@
 // Spiegel der Preload-API. Manuell synchron halten zu src/preload/index.ts.
+// IPC-Channel-Namen: src/main/ipc/channels.ts (Renderer kann nicht direkt importieren).
 
 export type AuthStatus = 'logged-out' | 'logged-in'