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/macos.rs

@@ -248,6 +248,24 @@ impl MacScsiTransport {
             exclusive: true,
         })
     }
+
+    /// Reset the drive to a known good state.
+    /// On macOS, we open the device, release exclusive access, wait for
+    /// the system to reclaim it, then the next open() re-acquires.
+    /// IOKit's USB layer handles device-level resets internally when the
+    /// exclusive access is released and re-acquired.
+    ///
+    /// NOTE: untested — macOS reset may need IOUSBDeviceInterface::ResetDevice()
+    /// for USB drives. This is a best-effort implementation.
+    pub fn reset(device: &Path) -> Result<()> {
+        // Opening and immediately dropping triggers release of exclusive access
+        // which forces IOKit to reset the device state.
+        if let Ok(transport) = Self::open(device) {
+            drop(transport); // Drop releases exclusive access + closes plugin
+        }
+        std::thread::sleep(std::time::Duration::from_secs(2));
+        Ok(())
+    }
 }
 
 impl Drop for MacScsiTransport {