Implement /rename command for Clan Owners #24

Description:
Currently, users have to open support tickets to change their Clan name or Tag. To improve user experience and reduce the manual workload for the support team, I propose adding a self-service command that allows Clan Owners to update these details directly.

Proposed Command:
/rename <new_name> <new_tag>

As a Clan Owner, I want to be able to rename my clan and change the associated tag without waiting for staff intervention, so that I can keep my clan's branding up to date instantly.

Requirements / Technical Details:

Validation:

• The <new_name> must follow existing character limits and filtered word lists.
• The <new_tag> must be unique and follow the established tag length constraints.

Cooldown:
To prevent abuse or spamming the global chat with name changes, a cooldown (e.g., 7 days) could be implemented.

Automating this process would streamline server administration.