Function generateUnifiedDiff

generateUnifiedDiff(
    originalContent: string,
    newContent: string,
    filePath: string,
    contextLines?: number,
): StreamingUnifiedFileDiff
Generates a unified diff between original and new file content
Parameters
- originalContent: string
  The original file content
- newContent: string
  The transformed file content
- filePath: string
  The file path for the diff header
- contextLines: number = 3
  Number of context lines to include (default: 3)
Returns StreamingUnifiedFileDiff
FileDiff object with unified diff and line counts