Agent Display Name control

Is your feature or enhancement related to a problem? Please describe. Chatwoot currently only supports a single display name per agent, which is always visible across all inboxes. There is no way to hide or override this name, even in scenarios where agent anonymity is required — such as when operating under a brand or a shared support identity. This limitation restricts flexibility for organizations that manage multiple inboxes with different visibility requirements, and may unintentionally expose agent identity in sensitive contexts. Describe the solution you'd like Introduce more flexible display name controls, including: Per-inbox agent display name override: Allow defining a custom agent display name per inbox. This enables the same agent to appear differently depending on the brand or use case of each inbox. Per-organization display name override: Allow an admin to set a default display name override across the whole organization for a given agent. Option to hide agen…