Drive recovery, reset on open, simplified DiscStream

- SgIoTransport::reset() — open/close/TUR/escalate on every open
- Drive::read() — single read method with error recovery (min speed,
  sleep 30s, retry, phase 1/2/3 escalation)
- Removed read_timeout, read_sectors, read_range — one read() method
- DiscStream simplified — no on_error/on_success/Recovery, delegates
  all error handling to Drive::read()
- IsoStream no longer decrypts — streams return raw bytes, pipeline
  handles decryption
- reset() on all platforms (Linux real, Windows/macOS stubs)
- Watchdog thread removed — kernel handles USB timeouts

src/scsi/mod.rs

@@ -60,7 +60,7 @@ pub trait ScsiTransport: Send {
     ) -> Result<ScsiResult>;
 }
 
-// ── Platform-agnostic open ──────────────────────────────────────────────────
+// ── Platform-agnostic open / reset ──────────────────────────────────────────
 
 /// Open a SCSI transport for the given device path.
 /// Selects the right backend for the current platform.
@@ -88,6 +88,31 @@ pub fn open(device: &Path) -> Result<Box<dyn ScsiTransport>> {
     }
 }
 
+/// Reset a SCSI device to a known good state. Platform-specific.
+/// On Linux: open/close fd cycle + TUR + SG_SCSI_RESET escalation.
+pub fn reset(device: &Path) -> Result<()> {
+    #[cfg(target_os = "linux")]
+    {
+        linux::SgIoTransport::reset(device)
+    }
+
+    #[cfg(target_os = "macos")]
+    {
+        macos::MacScsiTransport::reset(device)
+    }
+
+    #[cfg(target_os = "windows")]
+    {
+        windows::SptiTransport::reset(device)
+    }
+
+    #[cfg(not(any(target_os = "linux", target_os = "macos", target_os = "windows")))]
+    {
+        let _ = device;
+        Ok(())
+    }
+}
+
 // ── CDB builders (platform-agnostic) ────────────────────────────────────────
 
 /// SCSI INQUIRY response.