Add Character Counter and Input Length Validation in Chat Interface

Problem:

Currently, the chat input field does not provide any indication of the number of characters entered or warn users when the input exceeds a practical limit. Extremely long prompts may lead to poor user experience, increased API costs, or failures due to model token limits.

Expected Behavior:
Display a live character counter below the chat input.
Warn users when approaching the maximum input length.
Prevent submission when the configured limit is exceeded.
Display a clear validation message.

Benefits:
Improves user experience.
Prevents accidental oversized requests.
Reduces unnecessary API usage.
Makes application behavior more predictable.

Possible Solution:
Add a TextEditingController listener.
Display the current character count.
Disable the Send button after reaching the configured limit.
Keep the limit configurable through a constants file.

Additional Notes:
This enhancement only affects the frontend and does not require changes to the backend or AI
Hi, I would like to work on this issue under GSSoC 2026. Kindly assign it to me if it is available. Thank you!

Start at the chat input and its TextEditingController listener, then locate the constants file where the maximum length can be configured. Add the live count, approaching-limit warning, clear validation message, and Send-button prevention for over-limit input. Done means oversized prompts cannot be submitted and normal input remains usable.

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