Chapters, DVD subtitle palette, MKV track flags, progress total_bytes

Chapters:
- MPLS PlayList marks parsed (mark_type 1 = chapter)
- Chapter struct on DiscTitle (time_secs, name)
- MKV Chapters element with EditionEntry/ChapterAtom per mark
- 3 MPLS mark tests + 2 MKV chapter tests

DVD subtitle palette:
- IFO palette extraction (PGC offset 0xA4, 16 × YCbCr colors)
- YCbCr→RGB conversion for VobSub .idx format
- DvdSubParser codec_private returns formatted palette
- codec_data field on SubtitleStream flows through pipeline
- 5 palette tests (YCbCr conversion, formatting, overflow)

MKV track flags:
- FlagDefault: primary video/audio = 1, secondary = 0
- FlagForced: forced subtitles = 1
- Language: set from stream language code
- Already implemented, verified with 4 new tests

Progress total_bytes:
- IOStream trait: total_bytes() -> Option<u64>
- DiscStream, IsoStream: from disc_title.size_bytes
- M2tsStream, MkvStream: from file metadata on open
- NetworkStream, StdioStream, NullStream: None

316 tests total, all passing.

src/mux/codec/mod.rs

@@ -79,6 +79,16 @@ impl CodecParser for PassthroughParser {
 
 /// Create the appropriate parser for a codec.
 pub fn parser_for_codec(codec: Codec) -> Box<dyn CodecParser> {
+    parser_for_codec_with_data(codec, None)
+}
+
+/// Create the appropriate parser for a codec, with optional codec private data.
+///
+/// For DvdSub, `codec_data` should be the pre-formatted VobSub .idx palette header.
+pub fn parser_for_codec_with_data(
+    codec: Codec,
+    codec_data: Option<Vec<u8>>,
+) -> Box<dyn CodecParser> {
     match codec {
         Codec::H264 => Box::new(h264::H264Parser::new()),
         Codec::Hevc => Box::new(hevc::HevcParser::new()),
@@ -89,7 +99,7 @@ pub fn parser_for_codec(codec: Codec) -> Box<dyn CodecParser> {
         Codec::TrueHd => Box::new(truehd::TrueHdParser::new()),
         Codec::Pgs => Box::new(pgs::PgsParser::new()),
         Codec::Lpcm => Box::new(lpcm::LpcmParser::new()),
-        Codec::DvdSub => Box::new(dvdsub::DvdSubParser::new()),
+        Codec::DvdSub => Box::new(dvdsub::DvdSubParser::with_codec_data(codec_data)),
         _ => Box::new(PassthroughParser::new(true)),
     }
 }