[MKT_799]:feat/Add client-side daily message limit via localStorage

[jaaaaavier]

Description

We add a soft-limit to messages a user can send in a day

Changes Made

• Adds a useMessageLimit hook that tracks daily message usage in localStorage, resetting automatically at midnight
• Limit is set to 40 messages/day
• Blocks handleSend in ChatContext when the limit is reached
• Disables the chat input and shows the already-translated DailyLimit placeholder when the limit is hit

Additional Notes

Need to add a new environment variable

[sg-gs]

Remember to add the environment variable @jaaaaavier, I have just reviewed the code itself.