feat(mp4): add wave box for QuickTime audio decoder configuration

[nchitkara-xai]

Problem

The QuickTime siDecompressionParam atom (wave) wraps the decoder
configuration of QuickTime audio sample entries, so the esds of such an entry
is unreachable as an opaque UnknownBox payload.

Fix

A WaveBox container decodes frma and esds children (reachable as
AudioSampleEntryBox.Wave.Esds), and stays byte-exact for the irregular
content wave atoms carry in the wild:

• a child that does not decode cleanly — e.g. the 12-byte mp4a stub, or an
  esds whose decode consumes fewer bytes than its declared size — is kept as
  an UnknownBox with its bytes verbatim;
• a tail that is not a well-formed box — e.g. the terminator atom when
  written with size zero — is preserved verbatim in RawTail.

Decoding a wave body never fails, so garbage inside a wave cannot make a
sample entry undecodable (and cannot trip the ISO-layout fallback of #544).

Tests

Typed frma/esds decode, stub and malformed-esds fallback to UnknownBox,
size-zero terminator tail, programmatic construction, and a wave-wrapped esds
inside a version 1 sound sample entry — all byte-exact through both decode
paths. go test ./..., go vet, gofmt, golangci-lint pass.