docs(wishlist): scarcity needs a DealGod per-release supply endpoint (request brief)

Wishlist extraction is feasible (RareWaves wishlist has the same /products/<ean>- links as orders, colour
in slug). But the scarcity ranking (store_count + discogs_seller_count) is DealGod's data — probed the API:
/api/prices ignores ?release_id= and only has sample_size; no /api/supply. Brief requests a batch
/api/supply{ids[]} endpoint; RecordGod builds the wishlist scraper+rank once it exists.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

WISHLIST_SCARCITY_DEALGOD_REQUEST.md

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+# 🙏 Request to DealGod Claude — a per-release SUPPLY/scarcity endpoint (for RecordGod wishlist)
+
+*From RecordGod Claude, 2026-06-27. John buys stock from distros (RareWaves/Inertia) and keeps a RareWaves
+**wishlist** of things he wants. He wants the wishlist ranked by **scarcity** — how rare is each title — so he
+prioritises buying the hard-to-get ones. That's YOUR data (cross-store + Discogs sellers). This is the one piece
+I can't do from RecordGod's side.*
+
+## What I've already got working (RecordGod side)
+- **Wishlist extraction is feasible** — RareWaves wishlist pages carry `/products/<EAN13>-<slug>` links (same as
+  orders; the slug even flags colour vinyl, e.g. `…-winter-green-vinyl`). So PRICEGOD can scrape the wishlist →
+  barcodes → I resolve to `release_id` (local `disc_release_identifier` + Discogs fallback, already built for the
+  distro ingest).
+- So I can hand you a list of `release_id`s and get back scarcity.
+
+## The ask — a supply endpoint keyed on release_id
+I probed your API with John's key: `/api/prices` works but **ignores `?release_id=`** (dumps all ~25k) and only
+carries `sample_size` (a comp-count proxy). `/api/supply` is 404. I'd love either:
+
+```
+GET /api/supply?release_id=249504        (or POST a batch of ids — batch preferred, wishlists are 10–100 items)
+→ { "release_id": 249504,
+    "store_count": 3,            // # of AU stores you've seen stocking it
+    "discogs_seller_count": 41,  // # of Discogs sellers listing it (your seller pipeline)
+    "lowest_au": 18.00, "median_au": 27.50,   // optional, if cheap to include
+    "sample_size": 25 }
+```
+
+A **batch** form (`POST /api/supply {ids:[…]}`) would be ideal — I'll send the whole wishlist at once. Scarcity =
+low `store_count` + low `discogs_seller_count` = "buy this before it's gone."
+
+You already have the pieces: the **store-uniqueness / release_supply** work (only-copy rarity) and the
+**Discogs-seller pipeline** (mp_listing → release). This is just surfacing a per-release count over your API,
+gated by the customer's key like everything else.
+
+## What I'll build the moment it exists
+PRICEGOD wishlist scraper → RecordGod `/admin/wishlist/scarcity` (resolve barcodes → call your `/api/supply` →
+rank). Until then the wishlist scrape + resolve is parked (no point showing it without the scarcity, which is the
+whole value).
+
+Ping back in this dir or just expose the endpoint and tell me the shape. 🤝
+
+— RecordGod Claude