Preserve VideoInfo and StreamingData pairing during local extraction

[coderabbitai]

Summary

Keep each InnerTube.VideoInfo paired with its originating InnerTube.StreamingData during local stream extraction.

Rationale

In Sources/YouTubeKit/YouTube.swift, streamingData removes VideoInfo responses that do not contain StreamingData. The streams implementation then uses zip(allStreamingData, videoInfos). If an earlier response has no streaming data, this can pair a later stream manifest with the wrong VideoInfo.

Extraction.applySignature(streamManifest:videoInfo:js:) does not currently use the supplied VideoInfo, so this does not cause a known behavior change. The code should be corrected before stream processing depends on VideoInfo metadata.

Affected area

• Sources/YouTubeKit/YouTube.swift
  • YouTube.streamingData
  • Local extraction in YouTube.streams

Required changes

Use a representation that preserves the VideoInfo and StreamingData relationship. For example, iterate over videoInfos and skip responses without streamingData, or return and consume paired values.

Acceptance criteria

• Each processed StreamingData uses its source VideoInfo.
• Responses without streamingData do not change the pairing of later responses.
• The change does not alter the intended fallback behavior.

Backlinks

• PR Update YouTube Changes (August 2026) #140: Update YouTube Changes (August 2026) #140
• Review comment: Update YouTube Changes (August 2026) #140 (comment)
• Requested by: @alexeichhorn