[FEATURE] Alphabetize the list of agents when running `/agents`

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When running /agents, the list of agents is not listed in any meaningful order. This can make it hard to see if an agent I want already exists.

Proposed Solution

Sort the agents in alphabetical order.

Alternative Solutions

_No response_

Priority

Low - Nice to have

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_