Make download logs easier to read

[khanfarr]

• simplify the per-file progress output so each line just shows the counter, media type, filename, and capture time
• keep the success/failure status on the next line
• ensure we parse the timestamp once per item and gracefully skip any entries with missing/bad metadata
• document the 403 Forbidden error flow and how to re-export fresh JSON

[khanfarr]

thanks for creating this! thought these few tweaks would be helpful for my non technical friends :)