Audit fixes + DVD support foundation (IFO, PS demux, MPEG-2, CSS crack)

Audit fixes (14 critical, 22 warnings):
- UDF: bounds checks on all ICB/FID parsing from disc data
- SCSI Linux: saturating_sub on residual, CDB length guard, buffer size guard
- SCSI macOS: SCSITaskStatus u32 (was u8 — stack corruption)
- AACS: EC mod_inv returns infinity instead of panic, key reduced mod n
- AACS: do_handshake tries all host certs (was returning on first failure)
- H.264: bounds check on SPS < 4 bytes
- ContentReader: error on missing unit key (was zero-fill)
- KEYDB: flat redirect loop (was recursive), 100MB response limit, Windows HOME fallback
- ISO writer: AVDP extent order, partition length, allocation cap
- Network: removed TCP_NODELAY on bulk stream
- MKV: guard on u64::MAX seek
- disc.rs: saturating_sub on extent offset, simplified dead region code
- cargo fmt (610 violations), cargo clippy --fix (55 auto-fixes)

DVD support (new files):
- src/ifo.rs — IFO parser (VIDEO_TS.IFO, VTS_XX_0.IFO, PGC chains, cells, streams) — 13 tests
- src/mux/ps.rs — MPEG-2 Program Stream demuxer (pack headers, PES, private stream 1) — 12 tests
- src/mux/codec/mpeg2.rs — MPEG-2 video parser (sequence headers, I-frame detection) — 15 tests
- src/css/crack.rs — split-attack algorithm (LFSR cipher needs verification — test ignored)

226 tests total (was 186), 1 ignored (CSS crack needs cipher verification).

src/profile.rs

@@ -1,7 +1,7 @@
 //! Drive profile loading and matching.
 
-use serde::Deserialize;
 use crate::error::{Error, Result};
+use serde::Deserialize;
 
 /// Top-level profiles file — keyed by chipset + variant.
 #[derive(Debug, Deserialize)]
@@ -69,24 +69,31 @@ fn parse_hex4(s: &str) -> Result<[u8; 4]> {
     }
     let mut out = [0u8; 4];
     for i in 0..4 {
-        out[i] = u8::from_str_radix(&s[i*2..i*2+2], 16)
-            .map_err(|_| Error::ProfileParse)?;
+        out[i] = u8::from_str_radix(&s[i * 2..i * 2 + 2], 16).map_err(|_| Error::ProfileParse)?;
     }
     Ok(out)
 }
 
 fn deserialize_hex4<'de, D>(deserializer: D) -> std::result::Result<[u8; 4], D::Error>
-where D: serde::Deserializer<'de> {
+where
+    D: serde::Deserializer<'de>,
+{
     let s = String::deserialize(deserializer)?;
-    if s.is_empty() { return Ok([0; 4]); }
+    if s.is_empty() {
+        return Ok([0; 4]);
+    }
     parse_hex4(&s).map_err(serde::de::Error::custom)
 }
 
 fn deserialize_base64<'de, D>(deserializer: D) -> std::result::Result<Vec<u8>, D::Error>
-where D: serde::Deserializer<'de> {
+where
+    D: serde::Deserializer<'de>,
+{
     use base64::Engine;
     let s = String::deserialize(deserializer)?;
-    if s.is_empty() { return Ok(Vec::new()); }
+    if s.is_empty() {
+        return Ok(Vec::new());
+    }
     base64::engine::general_purpose::STANDARD
         .decode(&s)
         .map_err(serde::de::Error::custom)
@@ -101,8 +108,7 @@ pub fn load_bundled() -> Result<ProfilesFile> {
 }
 
 fn load_from_str(data: &str) -> Result<ProfilesFile> {
-    serde_json::from_str(data)
-        .map_err(|_| Error::ProfileParse)
+    serde_json::from_str(data).map_err(|_| Error::ProfileParse)
 }
 
 /// Find a profile matching a drive's INQUIRY fields.
@@ -126,7 +132,10 @@ pub fn find_by_drive_id(
                 && p.identity.vendor_specific.trim() == vs
                 && p.identity.firmware_date.trim() == date
         }) {
-            return Some(ProfileMatch { profile: p.clone(), platform });
+            return Some(ProfileMatch {
+                profile: p.clone(),
+                platform,
+            });
         }
 
         if let Some(p) = list.iter().find(|p| {
@@ -134,7 +143,10 @@ pub fn find_by_drive_id(
                 && p.identity.product_revision.trim() == r
                 && p.identity.vendor_specific.trim() == vs
         }) {
-            return Some(ProfileMatch { profile: p.clone(), platform });
+            return Some(ProfileMatch {
+                profile: p.clone(),
+                platform,
+            });
         }
     }
 
@@ -148,9 +160,10 @@ mod tests {
 
     fn make_drive_id(vendor: &str, rev: &str, vs: &str, date: &str) -> DriveId {
         let mut inquiry = vec![0u8; 96];
-        inquiry[8..8+vendor.len().min(8)].copy_from_slice(&vendor.as_bytes()[..vendor.len().min(8)]);
-        inquiry[32..32+rev.len().min(4)].copy_from_slice(&rev.as_bytes()[..rev.len().min(4)]);
-        inquiry[36..36+vs.len().min(7)].copy_from_slice(&vs.as_bytes()[..vs.len().min(7)]);
+        inquiry[8..8 + vendor.len().min(8)]
+            .copy_from_slice(&vendor.as_bytes()[..vendor.len().min(8)]);
+        inquiry[32..32 + rev.len().min(4)].copy_from_slice(&rev.as_bytes()[..rev.len().min(4)]);
+        inquiry[36..36 + vs.len().min(7)].copy_from_slice(&vs.as_bytes()[..vs.len().min(7)]);
         DriveId::from_inquiry(&inquiry, date)
     }