Initial implementation of Options Sidekick

Full-stack iOS options trading assistant:
- Python FastAPI backend with SQLite, APScheduler (15-min position monitor),
  APNs push notifications, and yfinance market data integration
- Signal engine: IV Rank (rolling HV proxy), SMA-50/200, swing-based
  support/resistance, earnings detection, signal strength scoring and
  noise-resistant SHA hash for change detection
- Recommendation engine: covered call and cash-secured put strike/expiry
  selection across 0DTE, 1DTE, weekly, and monthly horizons
- REST API: /devices, /portfolio, /recommendations, /positions, /signals, /alerts
- iOS SwiftUI app (iOS 17+): dashboard, recommendations, trades, portfolio,
  and alerts tabs with push notification deep-linking
- Unit + integration tests for signal engine and API layer

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

backend/app/routers/devices.py

@@ -0,0 +1,29 @@
+from datetime import datetime
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+
+from app.database import get_db
+from app.models.db_models import Device
+from app.models.schemas import DeviceRegister, DeviceResponse
+
+router = APIRouter(prefix="/devices", tags=["devices"])
+
+
+@router.post("/register", response_model=DeviceResponse)
+def register_device(body: DeviceRegister, db: Session = Depends(get_db)):
+    """Register or refresh an APNs device token."""
+    device = db.query(Device).filter(Device.apns_token == body.apns_token).first()
+
+    if device:
+        device.device_name = body.device_name or device.device_name
+        device.last_seen = datetime.utcnow()
+    else:
+        device = Device(
+            apns_token=body.apns_token,
+            device_name=body.device_name,
+        )
+        db.add(device)
+
+    db.commit()
+    db.refresh(device)
+    return device