Test a domain's PLP XPath config against any PLP URL. Extracts multiple product rows.
Step 1 — Load domain config
Step 2 — plp_xpaths config (editable)
Object with product_tiles (XPath string) and pdp_fields (dict of field → list of XPath strings).
Step 3 — Run scrape
If HTML is left blank, the page is fetched via FPM (may take 15–60 seconds).