Reads back the provenance record [render_record()] embedded in a rendered
`.html`, so you can ask which DGF produced a report you were handed.
Arguments
- path
Path to a rendered `.html` file.
Value
The record as a named list, or `NULL` when the file carries none
(e.g. it was produced before the record chunk existed).
Examples
if (FALSE) { # \dontrun{
rec <- read_render_record( "research-guide.html" )
rec$dgf_hash
} # }