Function createFlowCallback

createFlowCallback(
options: FlowCallbackOptions,
secret: string,
): TelegramInlineKeyboardButton
Creates a signed callback button for chat-side flow steps.

The encoded payload is kept within Telegram's callback-data limit and throws when the supplied flow data cannot fit safely.
Parameters
- options: FlowCallbackOptions
- secret: string
Returns TelegramInlineKeyboardButton
Example
```
const button = createFlowCallback(
  { text: "Confirm", flowId: "task-shop", action: "confirm" },
  "secret"
);
```