Add decrypt module, merge to one drive.read(), Disc::decrypt_keys()

- New decrypt.rs: DecryptKeys enum (AACS/CSS/None) + decrypt_sectors()
- Single drive.read() replaces read_disc/read_content (same SCSI READ(10))
- ContentReader and DiscStream use decrypt_sectors() (no duplicated crypto)
- Disc::decrypt_keys() exposes resolved keys for disc-to-ISO

src/drive/mod.rs

@@ -317,27 +317,8 @@ impl Drive {
         }
     }
 
-    pub fn read_disc(&mut self, lba: u32, count: u16, buf: &mut [u8]) -> Result<usize> {
-        let cdb = [
-            crate::scsi::SCSI_READ_10,
-            0x00,
-            (lba >> 24) as u8,
-            (lba >> 16) as u8,
-            (lba >> 8) as u8,
-            lba as u8,
-            0x00,
-            (count >> 8) as u8,
-            count as u8,
-            0x00,
-        ];
-        let result =
-            self.scsi
-                .as_mut()
-                .execute(&cdb, crate::scsi::DataDirection::FromDevice, buf, 5_000)?;
-        Ok(result.bytes_transferred)
-    }
-
-    pub fn read_content(&mut self, lba: u32, count: u16, buf: &mut [u8]) -> Result<usize> {
+    /// Read sectors from the disc. Raw SCSI READ(10).
+    pub fn read(&mut self, lba: u32, count: u16, buf: &mut [u8]) -> Result<usize> {
         let cdb = [
             crate::scsi::SCSI_READ_10,
             0x00,
@@ -424,7 +405,7 @@ impl Drive {
 
 impl SectorReader for Drive {
     fn read_sectors(&mut self, lba: u32, count: u16, buf: &mut [u8]) -> Result<usize> {
-        self.read_disc(lba, count, buf)
+        self.read(lba, count, buf)
     }
 }