Delete chat (for both sides, with permissions)

[mrsumanbiswas]

Give users the ability to delete entire conversations.

• “Delete chat” action should first clear the local chat history
• Optionally, allow the user to also request deletion from the server (this would delete the conversation for both parties, if the other side agrees or if it’s a legal/abuse scenario)
• For group chats, only admin can delete the group; members can leave
• Implement proper access control so that one user cannot arbitrarily delete another’s data without consent

Design the UI to be clear about what “delete” means (local vs. for everyone).