feat: custom formatter support

- format.ts: customFormat() uses child_process.execFile
- Template params: {KEY} {VALUE} {HEX_FILE}
- Value written to temp file, path passed via {HEX_FILE}
- 10s timeout, error handling
- StringEditor: 'custom' format option + command input
- Command persisted to localStorage
- i18n keys (zh-CN + en)

electron/main/ipc-handlers.ts

@@ -264,6 +264,9 @@ export function registerIpcHandlers(): void {
   ipcMain.handle('redis:detectFormat', (_e, value: string) => {
     return redis.detectFormat(value)
   })
+  ipcMain.handle('redis:customFormat', (_e, value: string, command: string, key: string) => {
+    return redis.customFormat(value, command, key)
+  })
 
   // Pub/Sub
   ipcMain.handle('redis:subscribe', async (_e, id: string, channels: string[], isPattern: boolean) => {