fix: beta trading pipeline — max_tokens default, approval re-enqueue, credentials

- Migration 031: change ai_agents/agent_variants max_tokens default
  from 32768 to 4096 (32768 exceeds vLLM context window, causing
  HTTP 400 on every extraction)
- API: re-enqueue approved orders to broker queue — previously
  approved orders sat in DB with nothing to execute them
- values-beta: enable TRADING_ENABLED, update Alpaca paper keys

infra/helm/stonks-oracle/values-beta.yaml

@@ -26,8 +26,7 @@ config:
   DEPLOY_STAGE: "beta"
   LOG_LEVEL: "DEBUG"
   JSON_LOGS: "true"
-  # Disable actual trading in beta — safety net
-  TRADING_ENABLED: "false"
+  TRADING_ENABLED: "true"
   # Use same infra services (shared postgres/redis/minio)
   POSTGRES_HOST: "postgresql-rw.postgresql-service.svc.cluster.local"
   POSTGRES_PORT: "5432"
@@ -61,8 +60,8 @@ secrets:
     MINIO_SECRET_KEY: "8fG3!v2rJ7$wN@9mLpQ6zXbC4tKdPqW1"
     REDIS_PASSWORD: "PSCh4ng3me!"
   broker:
-    BROKER_API_KEY: "PKEQXRJUTQCXJYLB4QOQC2LE6"
-    BROKER_API_SECRET: "Df1ZKL6d7F83CDM1jaFDh3K4BxQZJY9VoymoFvEaWiij"
+    BROKER_API_KEY: "PKRTP2PRRNCO3AYRGCK2FGWGMJ"
+    BROKER_API_SECRET: "dWhCubuyzTGDTPqtV1HXdUGhu8ZQB6EP4oui3GRyDTT"
     BROKER_BASE_URL: "https://paper-api.alpaca.markets"
   market:
     MARKET_DATA_API_KEY: "NPwKtrLvoBxcKt3Byp5PEvuZiBZU_d8E"