Add demo trading page, trader snapshot service and trading tables

Add trading_symbols, trading_analyses, trading_orders and trading_events.
The new trader service publishes account, position and open-order
snapshots of the Binance demo account to Redis every 3s. The /trading
page shows engine status, start/stop, balances, positions, the symbol
list with angle selection, open orders and the event timeline.

deploy/docker-compose.yml

@@ -24,6 +24,10 @@ services:
     <<: *backend
     command: [python, -m, alphapulse.market.worker]
 
+  trader:
+    <<: *backend
+    command: [python, -m, alphapulse.trading.engine]
+
   web:
     build:
       context: ../web