Refactor: drive discovery into platform files, no inline cfg

- drive/unix.rs: find_drives() + resolve_device() for Linux/macOS
- drive/windows.rs: find_drives() + resolve_device() + normalize_path() for Windows
- drive/mod.rs: clean delegation, no cfg branches
- scsi/windows.rs: SPTI transport only, no drive discovery

src/drive/windows.rs

@@ -0,0 +1,80 @@
+//! Windows drive discovery and device resolution.
+
+use crate::error::Result;
+use crate::identity::DriveId;
+use std::path::Path;
+
+pub fn find_drives() -> Vec<(String, DriveId)> {
+    let mut drives = Vec::new();
+
+    // Try CdRom0..CdRom15
+    for i in 0..16 {
+        let path = format!("\\\\.\\CdRom{}", i);
+        if let Ok(mut transport) = crate::scsi::open(Path::new(&path)) {
+            if let Ok(id) = DriveId::from_drive(transport.as_mut()) {
+                if !id.raw_inquiry.is_empty() && (id.raw_inquiry[0] & 0x1F) == 0x05 {
+                    drives.push((path, id));
+                }
+            }
+        }
+    }
+
+    // Also try drive letters if CdRom didn't find anything
+    if drives.is_empty() {
+        for letter in b'D'..=b'Z' {
+            let path = format!("{}:", letter as char);
+            if let Ok(mut transport) = crate::scsi::open(Path::new(&path)) {
+                if let Ok(id) = DriveId::from_drive(transport.as_mut()) {
+                    if !id.raw_inquiry.is_empty() && (id.raw_inquiry[0] & 0x1F) == 0x05 {
+                        drives.push((path, id));
+                    }
+                }
+            }
+        }
+    }
+
+    drives
+}
+
+pub fn resolve_device(path: &str) -> Result<(String, Option<String>)> {
+    Ok((normalize_path(path), None))
+}
+
+/// Normalize a device path to Windows \\.\X: format.
+///
+/// Accepts: "D:", "D:\\", "\\.\D:", "\\.\CdRom0"
+fn normalize_path(path: &str) -> String {
+    if path.starts_with("\\\\.\\") {
+        return path.to_string();
+    }
+    let trimmed = path.trim_end_matches('\\');
+    if trimmed.len() == 2 && trimmed.as_bytes()[1] == b':' {
+        return format!("\\\\.\\{}", trimmed);
+    }
+    if path.to_lowercase().starts_with("cdrom") {
+        return format!("\\\\.\\{}", path);
+    }
+    format!("\\\\.\\{}", path)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn normalize_drive_letter() {
+        assert_eq!(normalize_path("D:"), "\\\\.\\D:");
+        assert_eq!(normalize_path("E:\\"), "\\\\.\\E:");
+    }
+
+    #[test]
+    fn normalize_already_prefixed() {
+        assert_eq!(normalize_path("\\\\.\\D:"), "\\\\.\\D:");
+        assert_eq!(normalize_path("\\\\.\\CdRom0"), "\\\\.\\CdRom0");
+    }
+
+    #[test]
+    fn normalize_cdrom() {
+        assert_eq!(normalize_path("CdRom0"), "\\\\.\\CdRom0");
+    }
+}