For the supplied bytes, .txt has two files totaling 11 and .csv has two totaling 12. The total is four files and 23 bytes. Recreating the fixture with different newline encodings changes bytes, so preserve the downloaded files for the baseline check.

Critical check: The script does not alter input files, preview performs no export and invalid paths do not produce a false success.

Final project: Deliver the script, unchanged fixture, expected summary, preview evidence, error-case notes and README. Add one new .txt file to a copy and show that only the corresponding count and byte sum change.