Add Matter Lock Usercode Services (PoC)

[Coldaine]

This is a Proof of Concept to add set_lock_usercode and clear_lock_usercode services to the Matter integration, enabling PIN management for Matter locks via Home Assistant services. Implementation uses the legacy SetPinCode command for broad compatibility.

Future Work

Potential follow-up enhancements (to be discussed separately if this approach is accepted):

• Get/list usercodes - Query which code slots are in use
• Scheduled usercodes - Support for time-limited, recurring, or one-time PIN codes using Matter's user schedule features