feat: MD pipeline — market-data-service hardening + SenpAI NATS consumer

Producer (market-data-service):
- Backpressure: smart drop policy (heartbeats→quotes→trades preserved)
- Heartbeat monitor: synthetic HeartbeatEvent on provider silence
- Graceful shutdown: WS→bus→storage→DB engine cleanup sequence
- Bybit V5 public WS provider (backup for Binance, no API key needed)
- FailoverManager: health-based provider switching with recovery
- NATS output adapter: md.events.{type}.{symbol} for SenpAI
- /bus-stats endpoint for backpressure monitoring
- Dockerfile + docker-compose.node1.yml integration
- 36 tests (parsing + bus + failover), requirements.lock

Consumer (senpai-md-consumer):
- NATSConsumer: subscribe md.events.>, queue group senpai-md, backpressure
- State store: LatestState + RollingWindow (deque, 60s)
- Feature engine: 11 features (mid, spread, VWAP, return, vol, latency)
- Rule-based signals: long/short on return+volume+spread conditions
- Publisher: rate-limited features + signals + alerts to NATS
- HTTP API: /health, /metrics, /state/latest, /features/latest, /stats
- 10 Prometheus metrics
- Dockerfile + docker-compose.senpai.yml
- 41 tests (parsing + state + features + rate-limit), requirements.lock

CI: ruff + pytest + smoke import for both services
Tests: 77 total passed, lint clean
Co-authored-by: Cursor <cursoragent@cursor.com>

services/market-data-service/app/config.py

@@ -19,6 +19,9 @@ class Settings(BaseSettings):
     binance_ws_url: str = "wss://stream.binance.com:9443/ws"
     binance_rest_url: str = "https://api.binance.com"
 
+    # ── Bybit (backup crypto — no key needed) ──────────────────────────
+    bybit_ws_url: str = "wss://stream.bybit.com/v5/public/spot"
+
     # ── Alpaca (paper trading — free tier) ─────────────────────────────
     alpaca_key: str = ""
     alpaca_secret: str = ""
@@ -41,6 +44,11 @@ class Settings(BaseSettings):
     http_port: int = 8891
     metrics_enabled: bool = True
 
+    # ── NATS output adapter ─────────────────────────────────────────────
+    nats_url: str = ""  # e.g. "nats://localhost:4222"
+    nats_subject_prefix: str = "md.events"  # → md.events.trade.BTCUSDT
+    nats_enabled: bool = False
+
     # ── Logging ────────────────────────────────────────────────────────
     log_level: str = "INFO"
     log_sample_rate: int = 100  # PrintConsumer: log 1 out of N events
@@ -49,5 +57,9 @@ class Settings(BaseSettings):
     def alpaca_configured(self) -> bool:
         return bool(self.alpaca_key and self.alpaca_secret)
 
+    @property
+    def nats_configured(self) -> bool:
+        return bool(self.nats_url and self.nats_enabled)
+
 
 settings = Settings()