Initial commit: btcdata — BTC data backend service

Split from btcprice monolith. Owns DB, migrations, Binance WebSocket,
Kraken OHLC pollers, and exposes a JSON API with SSE price stream.

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

env/dev/clj/pmagnus/btcdata/dev_middleware.clj

@@ -0,0 +1,4 @@
+(ns pmagnus.btcdata.dev-middleware)
+
+(defn wrap-dev [handler _opts]
+  handler)

env/dev/clj/pmagnus/btcdata/env.clj

@@ -0,0 +1,11 @@
+(ns pmagnus.btcdata.env
+  (:require
+   [clojure.tools.logging :as log]
+   [pmagnus.btcdata.dev-middleware :refer [wrap-dev]]))
+
+(def defaults
+  {:init       (fn [] (log/info "\n-=[btcdata starting...dev/test profile]=-"))
+   :start      (fn [] (log/info "\n-=[btcdata started...dev/test profile]=-"))
+   :stop       (fn [] (log/info "\n-=[btcdata has shut down]=-"))
+   :middleware wrap-dev
+   :opts       {:profile :dev}})