Is there any documentation on how Ciscoworks LMS would work to discover Cisco IP Phones?
No, CDP is not required for UT phone acquisition, but it may be required for the switch to properly work with the phone.
UT does support the ability to acquire the PC end host, but it depends on the switch type as to how this is done. Cisco typically recommends such switch ports are not trunking, but rather have a primary and an auxiliary (i.e. voice) VLAN configured.
This is one of the core features of User Tracking. The documentation on UT should explain the steps in more detail. Essentially, UT relies on the CAM/MAC tables of switches managed by Campus Manager to build a list of IP phones as basic end hosts. Then, UT contacts the Call Managers managed by Campus to obtain specific IP phone details such as the phone number and registration status.