Function format_sync_json 

pub fn format_sync_json(r: &SyncReport) -> String

One SyncReport as a single JSON object, for sync --json.

text is exactly what format_sync prints, so a caller that has the object never has to render the digest a second way and never has to parse the counts back out of the prose. The MCP sync tool is that caller: it runs this binary and hands both halves straight to the assistant.