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/06_backfill_skin_condition_swept.sql

@@ -0,0 +1,44 @@
+-- ============================================================
+-- CS2 Skin Tracker — backfill skin_conditions.listings_swept_at
+-- Run against the skintracker database as the app role, ONCE,
+-- after the AddSkinConditionListingsSweptAt migration is applied
+-- and 05_fill_skin_conditions.sql has populated the wear bands.
+-- Idempotent: re-running only touches still-null bands.
+--
+-- Why: the catalogue sweep used to page each skin to completion
+-- as a single unit, so a non-null skins.listings_swept_at means
+-- EVERY wear of that skin was covered at that time. The sweep now
+-- checkpoints per wear band (skin_conditions.listings_swept_at).
+-- Without this backfill, every band of an already-swept skin would
+-- look never-swept and jump to the front of the queue, needlessly
+-- re-sweeping skins that are already current. Inheriting the skin's
+-- timestamp marks those bands as covered so the sweep moves on.
+--
+-- Only fills bands that are still null, so bands already swept under
+-- the new per-band logic keep their (newer) timestamp.
+-- ============================================================
+
+SET search_path = skintracker;
+
+UPDATE skin_conditions sc
+SET listings_swept_at = s.listings_swept_at
+FROM skins s
+WHERE sc.skin_id = s.id
+  AND s.listings_swept_at IS NOT NULL   -- skin was fully swept under the old per-skin logic
+  AND sc.listings_swept_at IS NULL;     -- don't overwrite bands already swept per-band
+
+-- ------------------------------------------------------------
+-- Sanity checks (optional)
+-- ------------------------------------------------------------
+-- Bands backfilled vs still never-swept:
+-- SELECT
+--   count(*) FILTER (WHERE listings_swept_at IS NOT NULL) AS swept,
+--   count(*) FILTER (WHERE listings_swept_at IS NULL)     AS never_swept
+-- FROM skin_conditions;
+--
+-- A previously-swept skin should now have all its bands stamped:
+-- SELECT s.name, sc.condition, sc.listings_swept_at
+-- FROM skin_conditions sc JOIN skins s ON s.id = sc.skin_id
+-- WHERE s.listings_swept_at IS NOT NULL
+-- ORDER BY s.name, sc.min_float
+-- LIMIT 20;