Function format_notes_as_json 

pub async fn format_notes_as_json(
    vault: &NoteVault,
    entries: &[(NoteEntryData, NoteContentData)],
    workspace_name: &str,
    query: Option<&str>,
    is_listing: bool,
) -> Result<String, Box<dyn Error>>

Format note entries as JSON output, fetching note content from vault