dm32: add DM-32UV support via dynamic memory discovery

[emuehlstein]

Summary

• add initial DM-32UV radio support to dmrconfig
• implement dynamic memory layout discovery using V-frame metadata rather than fixed offsets
• add DM-32 driver integration into radio detection and build flow
• include read/decode and write-path support for core structures used by DM-32UV codeplugs

Included Changes

• new DM-32 driver source and map definitions
• integration updates in radio selection/compatibility paths
• serial/protocol handling updates needed by DM-32UV
• small build and README updates needed for DM-32UV support

What Is Not Included

• research/reference captures and large reverse-engineering artifacts
• optional helper tooling/scripts used during investigation

Validation

• build: make clean && make (macOS)
• verified the resulting binary builds successfully with DM-32 objects linked

Notes

This PR intentionally keeps scope to the core upstreamable implementation so review is focused on driver behavior and integration.