v0.13.2: list_drives + drive_has_disc; SCSI primitives pub(crate)

Architectural cleanup. autorip + freemkv CLI were reimplementing drive
discovery (sysfs walking, type-5 filtering, sg-path construction) and
calling SCSI reset primitives directly. All of that hardware-aware code
moves into libfreemkv with two cheap public probes:

- DriveInfo + list_drives() — multi-OS enumeration (Linux/macOS/Windows)
  with peripheral-type-5 filtering and INQUIRY identity. Cheap.
- drive_has_disc(path) — single TUR with internal wedge recovery
  escalation (SCSI reset → USB reset → retry) hidden from callers.

USB-layer reset (USBDEVFS_RESET / IOUSBDeviceInterface::ResetDevice /
storport's combined reset) wired across all three platforms.

Visibility tightening — scsi::reset, scsi::usb_reset, and the timeout
constants are now pub(crate). Compile-time guarantee that no consumer
crate can issue SCSI commands directly.

233 lib tests pass; clippy clean.

src/drive/mod.rs

@@ -8,12 +8,15 @@
 
 pub mod capture;
 
+// Per-platform discovery helpers (the `pub(crate)` `find_drives` /
+// equivalents). Crate-public so `scsi/{linux,macos,windows}.rs` can
+// reuse the existing enumeration logic when shaping `DriveInfo`.
 #[cfg(target_os = "linux")]
-mod linux;
+pub(crate) mod linux;
 #[cfg(target_os = "macos")]
-mod macos;
+pub(crate) mod macos;
 #[cfg(windows)]
-mod windows;
+pub(crate) mod windows;
 
 use crate::error::{Error, Result};
 use crate::event::{Event, EventKind};