Add kraken_minute table with 15-second polling

1-minute OHLC candles from Kraken, polled every 15 seconds to keep the
in-progress candle fresh. Unlike hourly/daily pollers, this one keeps
the last candle and upserts it as it updates.

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

resources/migrations/20260313000000-create-kraken-minute.down.sql

@@ -0,0 +1 @@
+DROP TABLE IF EXISTS kraken_minute;

resources/migrations/20260313000000-create-kraken-minute.up.sql

@@ -0,0 +1,11 @@
+CREATE TABLE kraken_minute (
+  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

@@ -155,6 +155,23 @@ SELECT id, event_id, occurred_at, exchange, fiat_amount, fiat_currency,
 FROM deposits
 ORDER BY occurred_at DESC, id DESC
 
+-- :name upsert-kraken-minute! :! :n
+-- :doc Upsert a Kraken minute OHLC candle
+INSERT INTO kraken_minute (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-minute :? :1
+-- :doc Get the most recent Kraken minute candle timestamp
+SELECT ts FROM kraken_minute ORDER BY ts DESC LIMIT 1
+
 -- :name get-wallet-balances :? :*
 -- :doc Compute sats balance per wallet from events
 SELECT w.id, w.name,

resources/system.edn

@@ -63,6 +63,10 @@
  {:query-fn #ig/ref :db.sql/query-fn
   :enabled? #or [#env KRAKEN_ENABLED "true"]}
 
+ :kraken/ohlc-minute
+ {:query-fn #ig/ref :db.sql/query-fn
+  :enabled? #or [#env KRAKEN_ENABLED "true"]}
+
  :frankfurter/rates
  {:url      #or [#env FRANKFURTER_URL "http://localhost:8080"]
   :query-fn #ig/ref :db.sql/query-fn}