DVD vob_start absolute rebase + rc.5.3 audit fixes

- ifo.rs: rebase VTS title VOBS to absolute disc LBA (file_start_lba +
  vtstt_vobs); fixes DVD rips opening on the menu region instead of the
  movie (e.g. SOTL). Adds absolute-placement regression test.
- aacs/boil.rs: add mk_from_pk primitive (PK -> MK via MKB walk).
- dvdnav/: nav-VM command decoder + start-cell resolver seam, parked
  behind USE_NAV_RESOLVER (kept compiled, never executed).
- mux: FVI src.byte within-sector per spec; Unknown colour -> CICP
  unspecified (2,2,2,1); demux clear PCS -> NORMAL; ts.rs feed() base
  reset + boundary provenance fix.
- Assorted audit fixes (doc/comment/test accuracy) across the crate.

src/mux/codec/h264.rs

@@ -325,7 +325,8 @@ impl CodecParser for H264Parser {
 }
 
 /// Parse `(chroma_format_idc, bit_depth_luma_minus8, bit_depth_chroma_minus8)` from
-/// a High-Profile SPS NAL (profile_idc ∈ {100, 110, 122, 144}).
+/// a High-Profile SPS NAL (profile_idc ∈ `HIGH_PROFILES` — the 14 chroma/bit-depth
+/// extended profiles `codec_private` invokes this for).
 ///
 /// SPS RBSP layout (ITU-T H.264 §7.3.2.1.1) up to the fields we need:
 ///   byte 0        NAL header (already known to be type 7)