Add cs.money worker stack with per-worker IPRoyal residential proxy

Brings up the pull-model scraper: the .NET C2 hands skin+wear jobs to Python nodriver workers that scrape cs.money and post results back, plus the supporting Core/EFCore data model, migrations, and docker-compose orchestration.

IPRoyal proxying lets workers scale horizontally with a distinct residential exit IP each: every worker process mints its own sticky session at startup, and an in-process forwarding proxy injects the gateway auth so Chromium talks only to an auth-free localhost endpoint (zero CDP). On a Cloudflare challenge a worker rotates to a fresh session/IP and re-warms. Verified end-to-end against live IPRoyal: distinct US residential exits per worker and IP rotation on demand.

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

db/04_find_listings.sql

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+-- ============================================================
+-- CS2 Skin Tracker — find_listings()
+-- Run against the skintracker database as the app role (owner)
+-- to (re)create the function. Safe to re-run (CREATE OR REPLACE).
+--
+-- Purpose: look up active listings for a specific skin by weapon
+-- name + finish name, with an optional wear filter.
+--
+-- Examples:
+--   SELECT * FROM skintracker.find_listings('AK-47', 'Blue Laminate');
+--   SELECT * FROM skintracker.find_listings('m4a1-s', 'Player Two', 'ft');
+--   SELECT cs_float_listing_id, price, wear_name, float_value, is_stat_trak
+--   FROM skintracker.find_listings('M4A4', 'Howl', 'mw');
+-- ============================================================
+
+SET search_path = skintracker;
+
+CREATE OR REPLACE FUNCTION skintracker.find_listings(
+    p_weapon text,            -- e.g. 'AK-47', 'M4A4', 'M4A1-S' (case-insensitive)
+    p_skin   text,            -- e.g. 'Blue Laminate', 'Electric Blue' (case-insensitive)
+    p_wear   text DEFAULT NULL -- optional: fn | mw | ft | ww | bs (case-insensitive)
+)
+RETURNS SETOF skintracker.listings
+LANGUAGE plpgsql
+STABLE
+AS $$
+DECLARE
+    v_wear_name text;
+BEGIN
+    -- Map the optional wear abbreviation to the full wear name CSFloat reports.
+    -- NULL / blank means "any wear". An unrecognised value is an error rather than
+    -- a silent empty result.
+    IF p_wear IS NOT NULL AND btrim(p_wear) <> '' THEN
+        v_wear_name := CASE lower(btrim(p_wear))
+            WHEN 'fn' THEN 'Factory New'
+            WHEN 'mw' THEN 'Minimal Wear'
+            WHEN 'ft' THEN 'Field-Tested'
+            WHEN 'ww' THEN 'Well-Worn'
+            WHEN 'bs' THEN 'Battle-Scarred'
+            ELSE NULL
+        END;
+
+        IF v_wear_name IS NULL THEN
+            RAISE EXCEPTION 'Unknown wear abbreviation: "%". Use one of: fn, mw, ft, ww, bs.', p_wear;
+        END IF;
+    END IF;
+
+    RETURN QUERY
+    SELECT l.*
+    FROM skintracker.listings l
+    JOIN skintracker.skins    s ON s.id = l.skin_id
+    JOIN skintracker.weapons  w ON w.id = s.weapon_id
+    WHERE l.status = 'Active'
+      AND lower(w.name) = lower(btrim(p_weapon))
+      AND lower(s.name) = lower(btrim(p_skin))
+      AND (v_wear_name IS NULL OR l.wear_name = v_wear_name)
+    ORDER BY l.price ASC, l.float_value ASC;
+END;
+$$;
+
+-- If you use the optional read-only reporting role (see 02_readonly_role.sql),
+-- let it call the function:
+-- GRANT EXECUTE ON FUNCTION skintracker.find_listings(text, text, text) TO skintracker_readonly;