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>

build.clj

@@ -0,0 +1,28 @@
+(ns build
+  (:require [clojure.tools.build.api :as b]))
+
+(def lib 'pmagnus/btcdata)
+(def version "0.0.1-SNAPSHOT")
+(def target-dir "target")
+(def class-dir (str target-dir "/classes"))
+
+(def basis (delay (b/create-basis {:project "deps.edn"})))
+(def uber-file (str target-dir "/btcdata-standalone.jar"))
+
+(defn clean [_]
+  (b/delete {:path target-dir}))
+
+(defn uber [_]
+  (clean nil)
+  (b/copy-dir {:src-dirs   ["src/clj" "resources" "env/prod/resources" "env/prod/clj"]
+               :target-dir class-dir})
+  (b/compile-clj {:basis      @basis
+                  :ns-compile '[pmagnus.btcdata.core]
+                  :class-dir  class-dir})
+  (b/uber {:class-dir class-dir
+           :uber-file uber-file
+           :basis     @basis
+           :main      'pmagnus.btcdata.core}))
+
+(defn all [_]
+  (uber nil))