Add retry extraction context menu, increase error text limit

- Right-click packages with extraction errors shows "Extraktion
  wiederholen" option to manually retry
- Increase WinRAR error text from 240 to 500 chars for better
  diagnostics in logs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/shared/ipc.ts

@@ -31,5 +31,6 @@ export const IPC_CHANNELS = {
   QUIT: "app:quit",
   EXPORT_BACKUP: "app:export-backup",
   IMPORT_BACKUP: "app:import-backup",
-  OPEN_LOG: "app:open-log"
+  OPEN_LOG: "app:open-log",
+  RETRY_EXTRACTION: "queue:retry-extraction"
 } as const;

src/shared/preload-api.ts

@@ -42,6 +42,7 @@ export interface ElectronApi {
   exportBackup: () => Promise<{ saved: boolean }>;
   importBackup: () => Promise<{ restored: boolean; message: string }>;
   openLog: () => Promise<void>;
+  retryExtraction: (packageId: string) => Promise<void>;
   onStateUpdate: (callback: (snapshot: UiSnapshot) => void) => () => void;
   onClipboardDetected: (callback: (links: string[]) => void) => () => void;
   onUpdateInstallProgress: (callback: (progress: UpdateInstallProgress) => void) => () => void;