Core of the Rust MediaInfo engine — transliteration of MediaInfoLib's
File__Analyze infrastructure. Provides the byte-reader surface that
every parser uses (Get_B*, Get_L*, Peek_*, Skip_*) plus the
element tree, stream model, config, and event dispatch.
All methods return native Rust types (u8, u16, u32, u64, f32,
f64) rather than out-parameters or type aliases.