Expose the LibreDrive profile catalog as a curated public API on `ld`:
`ld::profiles()` returns the `Profiles` object (with `.get(drive_id)`) and
`ld::profile(filter)` finds one — the catalog of supported drives, queried
without unlocking. The unlock mechanism (firmware blobs, upload sequence, CDB
wire format) stays private; `LibreDrive` is pub(crate), reached only via
`all_unlockers()`.
The unlock-handshake wire format the bdemu test-emulator needs to impersonate a
drive (`UNLOCK_MARKER`, `is_unlock_read_buffer`) is behind a non-default
`emulation` feature; the `cdb` module compiles only under it. Rename the
`ScsiError` error variant to `Scsi` (matches css), gate the test-only
`load_bundled` and `SCSI_STATUS_CHECK_CONDITION`. Clippy-clean in both feature
configs; 86/89 tests pass.
Matthew Jackson
30f653f7f4