audit: module-by-module code audit fixes and test coverage

Lands the code-audit branches for aacs, css, keys, labels, udf, ifo and
dvd, bdnav/mpls/clpi, disc/bluray, extract, io, scsi, the mkv, mp4,
network and mpg muxers, the audio and video codecs, and CI. Fixes
include MKB and FMTS validation, UDF bounds, IFO fallback to the BUP,
DTS Express framing, MPEG-2 field pairing and mpg re-basing; the rest
pins existing behaviour with tests.

tests/udf_tests.rs

@@ -1,5 +1,6 @@
 //! UDF parser tests using a MockSectorReader.
 
+use libfreemkv::error::Error;
 use libfreemkv::error::Result;
 use libfreemkv::{SectorSource, read_filesystem};
 use std::collections::HashMap;
@@ -208,59 +209,15 @@ fn make_file_icb(data_lba: u32, data_len: u32, file_size: u64) -> Vec<u8> {
 
 // ── Tests ──────────────────────────────────────────────────────────────────
 
-#[test]
-fn mock_sector_reader_roundtrip() {
-    let mut reader = MockSectorReader::new();
-
-    // Write a recognizable pattern to sector 100
-    let mut data = vec![0u8; SECTOR_SIZE];
-    data[0] = 0xAB;
-    data[1] = 0xCD;
-    data[2047] = 0xFF;
-    reader.set_sector(100, data.clone());
-
-    // Read it back
-    let mut buf = vec![0u8; SECTOR_SIZE];
-    let n = reader.read_sectors(100, 1, &mut buf, true).unwrap();
-    assert_eq!(n, SECTOR_SIZE);
-    assert_eq!(buf[0], 0xAB);
-    assert_eq!(buf[1], 0xCD);
-    assert_eq!(buf[2047], 0xFF);
-
-    // Reading an unmapped sector returns zeros
-    let mut buf2 = vec![0xFFu8; SECTOR_SIZE];
-    let n2 = reader.read_sectors(999, 1, &mut buf2, true).unwrap();
-    assert_eq!(n2, SECTOR_SIZE);
-    assert_eq!(buf2[0], 0);
-    assert_eq!(buf2[2047], 0);
-}
-
-#[test]
-fn mock_sector_reader_multi_sector() {
-    let mut reader = MockSectorReader::new();
-
-    let mut s10 = vec![0u8; SECTOR_SIZE];
-    s10[0] = 10;
-    reader.set_sector(10, s10);
-
-    let mut s11 = vec![0u8; SECTOR_SIZE];
-    s11[0] = 11;
-    reader.set_sector(11, s11);
-
-    // Read 2 consecutive sectors
-    let mut buf = vec![0u8; SECTOR_SIZE * 2];
-    let n = reader.read_sectors(10, 2, &mut buf, true).unwrap();
-    assert_eq!(n, SECTOR_SIZE * 2);
-    assert_eq!(buf[0], 10);
-    assert_eq!(buf[SECTOR_SIZE], 11);
-}
-
 #[test]
 fn read_filesystem_no_avdp() {
     // Empty reader — sector 256 is all zeros, tag_id=0 != 2
     let mut reader = MockSectorReader::new();
     let result = read_filesystem(&mut reader);
-    assert!(result.is_err(), "should fail when no AVDP at sector 256");
+    assert!(
+        matches!(result, Err(Error::UdfNotFilesystem)),
+        "no AVDP at sector 256 is the deterministic not-UDF verdict"
+    );
 }
 
 #[test]
@@ -272,7 +229,10 @@ fn read_filesystem_bad_avdp_tag() {
     reader.set_sector(256, bad);
 
     let result = read_filesystem(&mut reader);
-    assert!(result.is_err(), "should fail when AVDP tag_id is not 2");
+    assert!(
+        matches!(result, Err(Error::UdfNotFilesystem)),
+        "AVDP tag_id != 2 is the not-UDF verdict"
+    );
 }
 
 #[test]
@@ -285,8 +245,8 @@ fn read_filesystem_no_partition_descriptor() {
 
     let result = read_filesystem(&mut reader);
     assert!(
-        result.is_err(),
-        "should fail when no partition descriptor in VDS"
+        matches!(result, Err(Error::UdfNotFilesystem)),
+        "no partition descriptor is the not-UDF verdict"
     );
 }
 
@@ -305,7 +265,10 @@ fn read_filesystem_bad_fsd_tag() {
     // FSD should be at sector partition_start but we leave it as zeros (tag_id=0 != 256).
 
     let result = read_filesystem(&mut reader);
-    assert!(result.is_err(), "should fail when FSD tag_id is not 256");
+    assert!(
+        matches!(result, Err(Error::UdfNotFilesystem)),
+        "FSD tag_id != 256 is the not-UDF verdict"
+    );
 }
 
 #[test]
@@ -455,16 +418,3 @@ fn find_dir_case_insensitive() {
     assert!(fs.find_dir("BDMV/STREAM").is_none());
     assert!(fs.find_dir("NONEXISTENT").is_none());
 }
-
-#[test]
-fn sector_reader_is_object_safe() {
-    // Verify SectorSource can be used as a trait object
-    let mut reader = MockSectorReader::new();
-    reader.set_sector(0, vec![42u8; SECTOR_SIZE]);
-
-    let dyn_reader: &mut dyn SectorSource = &mut reader;
-    let mut buf = vec![0u8; SECTOR_SIZE];
-    let n = dyn_reader.read_sectors(0, 1, &mut buf, true).unwrap();
-    assert_eq!(n, SECTOR_SIZE);
-    assert_eq!(buf[0], 42);
-}