Try the Kroger search API

- **Filters and sort apply to the `json_api` path only.** When any of them is set and that path fails, the request returns an error instead of falling back to the rendered page — the HTML path cannot honor these filters, so returning its unfiltered results would be wrong. Unfiltered requests still fall back as before. - Each result's `upc` is usable directly as the `upc` query parameter to [`/kroger/product`](kroger-product.md). - For browsing a specific product category instead of keyword search, see [`/kroger/category`](kroger-category.md), which returns results in this same shape. - `total_count` reflects the number of results Kroger's own page reports as loaded, not necessarily every result matching the query — Kroger's search page loads results in batches behind a "Load More Results" control. - `source` reports which upstream path served the response: `json_api` (Kroger's own search API, the primary path) or `html` (the rendered-page fallback, used only when the JSON path is unavailable). - **Pagination is real on the `json_api` path** — it uses Kroger's own page offset/size, and `has_more` reports whether further pages exist. On the `html` fallback `has_more` is always `false` and paging past page 1 remains best-effort. - `facets` lists the refinement groups Kroger offers for the query (brands, nutrition, savings, price range and more), each value with its result count. Only populated on the `json_api` path. - `brand` and `stock_level` are populated on the `json_api` path only; the rendered result cards carry neither. - A missing `query` returns `400` before any upstream request is made.