Add Kraken hourly OHLC poller with database storage

Fetches Bitcoin hourly candles from the Kraken public REST API
and upserts them into a kraken_hour table on a 5-minute poll interval,
following the existing Integrant component pattern.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

resources/migrations/20260218000000-create-kraken-hour.down.sql

@@ -0,0 +1 @@
+DROP TABLE kraken_hour;

resources/migrations/20260218000000-create-kraken-hour.up.sql

@@ -0,0 +1,11 @@
+CREATE TABLE kraken_hour (
+  ts          BIGINT         NOT NULL PRIMARY KEY,
+  open        NUMERIC(18,8)  NOT NULL,
+  high        NUMERIC(18,8)  NOT NULL,
+  low         NUMERIC(18,8)  NOT NULL,
+  close       NUMERIC(18,8)  NOT NULL,
+  vwap        NUMERIC(18,8)  NOT NULL,
+  volume      NUMERIC(24,8)  NOT NULL,
+  trade_count INTEGER        NOT NULL,
+  created_at  TIMESTAMPTZ    NOT NULL DEFAULT NOW()
+);

resources/queries.sql

@@ -7,3 +7,21 @@ INSERT INTO binance_price (price) VALUES (:price)
 -- :name get-latest-binance-price :? :1
 -- :doc Get the most recent Binance BTC price
 SELECT price, recorded_at FROM binance_price ORDER BY id DESC LIMIT 1
+
+-- :name upsert-kraken-hour! :! :n
+-- :doc Upsert a Kraken hourly OHLC candle
+INSERT INTO kraken_hour (ts, open, high, low, close, vwap, volume, trade_count)
+VALUES (:ts, :open, :high, :low, :close, :vwap, :volume, :trade-count)
+ON CONFLICT (ts) DO UPDATE
+SET open = EXCLUDED.open,
+    high = EXCLUDED.high,
+    low  = EXCLUDED.low,
+    close = EXCLUDED.close,
+    vwap  = EXCLUDED.vwap,
+    volume = EXCLUDED.volume,
+    trade_count = EXCLUDED.trade_count
+
+-- :name get-latest-kraken-hour :? :1
+-- :doc Get the most recent Kraken hourly candle by timestamp
+SELECT ts, open, high, low, close, vwap, volume, trade_count, created_at
+FROM kraken_hour ORDER BY ts DESC LIMIT 1

resources/system.edn

@@ -56,4 +56,8 @@
 
  :ws/binance
  {:query-fn #ig/ref :db.sql/query-fn
-  :uri      "wss://stream.binance.com:9443/ws/btcusdt@trade"}}
+  :uri      "wss://stream.binance.com:9443/ws/btcusdt@trade"}
+
+ :kraken/ohlc
+ {:query-fn    #ig/ref :db.sql/query-fn
+  :interval-ms 300000}}