Add unshackle.core.cdm.detect helpers to classify CDMs consistently across local and remote backends.
- Add is_playready_cdm/is_widevine_cdm for DRM selection across pyplayready, pywidevine, and wrappers
- Add is_remote_cdm/is_local_cdm/cdm_location so services can branch on CDM execution location
- Switch core DASH/HLS parsing, track DRM selection, and dl CDM switching away from brittle isinstance/DecryptLabs-only checks
- Make unshackle.core.cdm import-light via lazy __getattr__ so optional CDM deps are only imported when needed
6b8a8ba8a8