* perf(producer): assemble chunks that carry audio under one faststart index
Reads each chunk's moov, merges the sample tables into one moov at the front, and writes
the chunks' mdat payloads after it unchanged: the same bytes storage can copy into place.
The assembler no longer needs the plan audio for such plans.
* perf(aws-lambda): build the final mp4 inside S3 with its index up front
The Lambda plan asks chunks to carry their audio. Assemble writes the faststart header as
part 1 of a multipart upload and copies each chunk's mdat payload with UploadPartCopy, so
the video bytes never pass through the function; any failure aborts the upload.
* fix(engine): a chunk's first frame shows its own time, not the composition's opening frame
* fix(producer): stitch silent AAC tails and clean failed outputs
* fix(producer): open stitched chunks read-only with an explicit mode
* chore(aws-lambda): raise the package size budget for S3-side MP4 assembly
handler.js and index.js each bundle the new S3 stitch code (+5,550 bytes apiece) and s3Stitch.d.ts adds 970: +3,479 packed and +12,070 unpacked over main, measured with the CI pack. The budget rises by exactly that delta.
* fix(aws-lambda): v1 plans give chunks their audio too, so both protocols match
* perf(producer): plans whose chunks carry audio encode it once, at the frames' exact length
* test(producer): terminate the plan audio ffprobe argv like every other probe
Miguel Ángel
70fbe32f8d