Integrate WebCodecs API for MPEG-2/H.264 video decoding in ATSC streams (#224)

* Initial plan

* feat: Add ATSCVideoDecoder and VideoRenderer classes

Co-authored-by: alexthemitchell <5687158+alexthemitchell@users.noreply.github.com>

* feat: Integrate video decoder with useATSCPlayer hook

Co-authored-by: alexthemitchell <5687158+alexthemitchell@users.noreply.github.com>

* fix: Resolve linting issues and finalize implementation

Co-authored-by: alexthemitchell <5687158+alexthemitchell@users.noreply.github.com>

* fix: Address PR review comments - fix timestamp conversion, frame buffer, PTS/DTS parsing, and error handling

Co-authored-by: alexthemitchell <5687158+alexthemitchell@users.noreply.github.com>

* fix: Improve division by zero guards and add comprehensive tests

Co-authored-by: alexthemitchell <5687158+alexthemitchell@users.noreply.github.com>

* fix: Remove redundant check and fix test issues

Co-authored-by: alexthemitchell <5687158+alexthemitchell@users.noreply.github.com>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: alexthemitchell <5687158+alexthemitchell@users.noreply.github.com>

Author: Copilot