Knockoff: Shopping Filter

New: Knockoff now filters Amazon's Deals, Best Sellers, and New Releases pages, plus the "related items" carousels on product and home pages — not just search and browse results. New: a "Find US alternatives" button on product pages opens a list of similar listings whose seller we can name, with US sellers flagged. To pick which products are worth covering, Knockoff reports the products you open — the product, never who was looking. On by default; turn it off with "Help pick US alternatives" in settings. New: listings now show a small flag for where the seller is based, right on the product image in search results and on the product page, so you can see a listing's origin at a glance. Flags are display-only and never change what Knockoff filters. On by default; you can turn them off in settings. New: when Knockoff doesn't recognize a seller yet, it shows a "Where from?" chip — opening the seller page adds their country to a community-built map that every install benefits from, and the countries you help map fill in a personal passport. Only seller IDs and countries are ever sent, never anything about you, your search, or the products. Improved: the seller country chip is now clickable everywhere. A resolved country used to be a dead label; both it and "Where from?" now open the seller's Amazon profile, where you can check the claim for yourself. Improved: the community seller map now reads the whole business-identity block Amazon already publishes on a seller's profile page (registered name, address and contact details, disclosed there under marketplace-transparency laws). Only the seller's public details are contributed, never anything about you. Revisiting a seller page now refreshes what we hold, so a seller that moves gets noticed. Fixed: the seller-map contribution stats could show a community total smaller than your own count. The two numbers now count the same thing. Plus under-the-hood reliability and anti-abuse hardening for the community seller map.