Function rateLimit

rateLimit(options?: RateLimitOptions): MiddlewareFn
Creates an in-memory sliding window rate limiter middleware.

Prevents flood limits and excessive requests by throttling updates per user or chat.
Parameters
- options: RateLimitOptions = {}
  Configuration options for the rate limiter.
Returns MiddlewareFn
A MiddlewareFn ready to be used with app.use().
Example
```
// Limit each user to max 3 messages per 2 seconds
app.use(rateLimit({
  windowMs: 2000,
  limit: 3,
  onLimitExceeded: async (ctx) => {
    await ctx.reply("Slow down! Please wait a moment.");
  },
}));
```