feat(w2): add PackService for .novel and .novel-all export/import

Introduce pack-bootstrap chunk, ZipArchive-based PackService with progress IPC,
book registry import helpers, and IT-PACK-01 / IT-ALL-02 integration tests.

Co-authored-by: Cursor <cursoragent@cursor.com>

electron.vite.config.ts

@@ -9,9 +9,10 @@ export default defineConfig({
       rollupOptions: {
         input: {
           index: resolve(__dirname, 'src/main/index.ts'),
-          'import-bootstrap': resolve(__dirname, 'src/main/import-bootstrap.ts')
+          'import-bootstrap': resolve(__dirname, 'src/main/import-bootstrap.ts'),
+          'pack-bootstrap': resolve(__dirname, 'src/main/pack-bootstrap.ts')
         },
-        external: ['mammoth', 'marked']
+        external: ['mammoth', 'marked', 'archiver', 'extract-zip']
       }
     }
   },