Character or token count is shown when approaching input limits

When the app enforces an input length limit via a maxLength attribute or server-side truncation, users have no way to see how close they are to the ceiling until their prompt is silently cut off or rejected. Long prompts — the exact high-intent content that benefits most from an AI — are the most likely to hit this limit, and silent truncation produces degraded or confusing responses that the user attributes to model quality rather than input handling. A visible counter at the threshold eliminates that failure mode entirely.

In src/components/chat/ChatInput.tsx, render a character counter once the user crosses eighty percent of the configured maxLength, and swap it to a destructive color at ninety-five percent so the warning escalates as the limit approaches.

{maxLength && input.length > maxLength * 0.8 && (
  <span className={cn("text-xs", input.length > maxLength * 0.95 ? "text-destructive" : "text-muted-foreground")}>
    {input.length} / {maxLength}
  </span>
)}