0.31.0: hardening and correctness pass across mux, codec, AACS/CSS, UDF/MPLS/CLPI, recovery, drive/SCSI, labels, and I/O

Library-wide review-and-fix pass: tightened AACS keydb/handshake/variant
handling and trailing-partial-unit policy, corrected MPLS mark offset and
added UDF allocation bounds, hardened the mux/codec framing and M2TS paths,
guarded SCSI READ CAPACITY short transfers and unified error mapping, added
overflow guards on untrusted disc input, and made prefetch shutdown
deterministic. Release profile now builds with thin LTO + single codegen unit.

src/io/file_sector_source/macos.rs

@@ -8,32 +8,22 @@
 use std::fs::File;
 use std::os::unix::io::AsRawFd;
 
-/// `F_RDADVISE` opcode — not in libc's named constants on all SDKs.
-const F_RDADVISE: libc::c_int = 44;
-
 /// Cap on the byte length we pass to `F_RDADVISE`. Asking for a
 /// multi-GB readahead window is counterproductive — the OS doesn't
 /// have that much cache to throw at one fd. 64 MiB is generous for
-/// our use case (sweep, mux) and matches the byte-channel cap so the
-/// kernel's prefetch ≥ our app-level pipeline depth.
+/// our use case (sweep, mux) so the kernel's prefetch ≥ our app-level
+/// pipeline depth.
 const RDADVISE_MAX_BYTES: i64 = 64 * 1024 * 1024;
 
-/// `radvisory` per `<sys/fcntl.h>`. repr(C) layout is stable.
-#[repr(C)]
-struct RadAdvisory {
-    ra_offset: libc::off_t,
-    ra_count: libc::c_int,
-}
-
 pub(super) fn hint_sequential(file: &File, len_bytes: u64) {
     let bytes = (len_bytes as i64).min(RDADVISE_MAX_BYTES);
-    let mut ra = RadAdvisory {
+    let mut ra = libc::radvisory {
         ra_offset: 0,
         ra_count: bytes as libc::c_int,
     };
     // Best-effort.
     unsafe {
-        libc::fcntl(file.as_raw_fd(), F_RDADVISE, &mut ra);
+        libc::fcntl(file.as_raw_fd(), libc::F_RDADVISE, &mut ra);
     }
 }
 
@@ -52,11 +42,12 @@ pub(super) fn drop_window(_file: &File, _start: u64, _len: u64) {}
 /// returns immediately.
 pub(super) fn prefetch(file: &File, offset: u64, len: u64) {
     let bytes = (len as i64).min(RDADVISE_MAX_BYTES);
-    let mut ra = RadAdvisory {
+    let mut ra = libc::radvisory {
         ra_offset: offset as libc::off_t,
         ra_count: bytes as libc::c_int,
     };
+    // Best-effort — kernel hint only.
     unsafe {
-        libc::fcntl(file.as_raw_fd(), F_RDADVISE, &mut ra);
+        libc::fcntl(file.as_raw_fd(), libc::F_RDADVISE, &mut ra);
     }
 }