feat: multi-format viewer (Text/Hex/JSON/Binary/Gzip/Deflate/Brotli)

- New format.ts: decodeValue + detectFormat using Node.js zlib
- IPC: redis:decodeValue, redis:detectFormat
- StringEditor: format selector dropdown with auto-detect
- Monaco editor shows decoded value, read-only for compressed formats
- Auto-detect: JSON, Gzip (1f 8b), Deflate (78 xx), non-printable → Hex
- i18n keys for all formats (zh-CN + en)

electron/main/ipc-handlers.ts

@@ -257,6 +257,14 @@ export function registerIpcHandlers(): void {
     redis.clearLog()
   })
 
+  // Format decode
+  ipcMain.handle('redis:decodeValue', (_e, value: string, format: string) => {
+    return redis.decodeValue(value, format as any)
+  })
+  ipcMain.handle('redis:detectFormat', (_e, value: string) => {
+    return redis.detectFormat(value)
+  })
+
   // Pub/Sub
   ipcMain.handle('redis:subscribe', async (_e, id: string, channels: string[], isPattern: boolean) => {
     try {