Split data layer into btcdata service

Remove DB, Binance WebSocket, and Kraken pollers from btcprice.
UI now uses vanilla EventSource connecting to btcdata for live
price updates. btcprice is now a pure UI service with no database.

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

env/dev/clj/user.clj

@@ -1,6 +1,5 @@
 (ns user
   (:require
-   [clojure.tools.logging :as log]
    [integrant.core :as ig]
    [integrant.repl :refer [go halt reset reset-all set-prep!]]
    [integrant.repl.state :as state]
@@ -19,30 +18,6 @@
      (-> (config/system-config {:profile :test})
          (ig/expand)))))
 
-(defn reset-db []
-  (let [sys (or @pmagnus.btcprice.core/system
-                integrant.repl.state/system)]
-    (when-let [mig (:db.sql/migrations sys)]
-      (migratus.core/reset mig)
-      (log/info "Database reset complete"))))
-
-(defn rollback []
-  (let [sys (or @pmagnus.btcprice.core/system
-                integrant.repl.state/system)]
-    (when-let [mig (:db.sql/migrations sys)]
-      (migratus.core/rollback mig))))
-
-(defn migrate []
-  (let [sys (or @pmagnus.btcprice.core/system
-                integrant.repl.state/system)]
-    (when-let [mig (:db.sql/migrations sys)]
-      (migratus.core/migrate mig))))
-
-(defn query-fn []
-  (let [sys (or @pmagnus.btcprice.core/system
-                integrant.repl.state/system)]
-    (:db.sql/query-fn sys)))
-
 (comment
   (dev-prep!)
   (go)