refactor: address python review findings

- Move FRED credential registration to FastAPI lifespan (was fragile
  import-order-dependent side-effect)
- Add noqa E402 annotations for imports after curl_cffi patch
- Fix all return type hints: bare dict -> dict[str, Any]
- Move yfinance import to module level (was inline in functions)
- Fix datetime.now() -> datetime.now(tz=timezone.utc) in openbb_service
- Add try/except error handling to Group B service functions
- Fix dict mutation in relative_rotation (immutable pattern)
- Extract _classify_rrg_quadrant helper function
- Fix type builtin shadow in routes_economy (type -> gdp_type)
- Fix falsy int guard (if year: -> if year is not None:)
- Remove user input echo from error messages

technical_service.py

@@ -411,13 +411,12 @@ async def get_relative_rotation(
     Returns RS-Ratio and RS-Momentum for each symbol, indicating
     which RRG quadrant they occupy (Leading/Weakening/Lagging/Improving).
     """
-    from datetime import datetime, timedelta, timezone
+    from datetime import datetime, timedelta, timezone as tz
 
-    start = (datetime.now(tz=timezone.utc) - timedelta(days=days)).strftime("%Y-%m-%d")
+    start = (datetime.now(tz=tz.utc) - timedelta(days=days)).strftime("%Y-%m-%d")
     all_symbols = ",".join(symbols + [benchmark])
 
     try:
-        # Fetch multi-symbol historical data in one call
         hist = await asyncio.to_thread(
             obb.equity.price.historical,
             all_symbols,
@@ -434,26 +433,17 @@ async def get_relative_rotation(
             study=study,
         )
         items = to_list(result)
-        # Return the latest data point per symbol
-        latest_by_symbol: dict[str, dict] = {}
+
+        latest_by_symbol: dict[str, dict[str, Any]] = {}
         for item in items:
             sym = item.get("symbol")
             if sym and sym != benchmark:
                 latest_by_symbol[sym] = item
 
-        entries = list(latest_by_symbol.values())
-        for entry in entries:
-            rs_ratio = entry.get("rs_ratio")
-            rs_momentum = entry.get("rs_momentum")
-            if rs_ratio is not None and rs_momentum is not None:
-                if rs_ratio > 100 and rs_momentum > 100:
-                    entry["quadrant"] = "Leading"
-                elif rs_ratio > 100 and rs_momentum <= 100:
-                    entry["quadrant"] = "Weakening"
-                elif rs_ratio <= 100 and rs_momentum <= 100:
-                    entry["quadrant"] = "Lagging"
-                else:
-                    entry["quadrant"] = "Improving"
+        entries = [
+            {**item, "quadrant": _classify_rrg_quadrant(item)}
+            for item in latest_by_symbol.values()
+        ]
 
         return {
             "symbols": symbols,
@@ -466,6 +456,21 @@ async def get_relative_rotation(
         return {"symbols": symbols, "error": "Failed to compute relative rotation"}
 
 
+def _classify_rrg_quadrant(item: dict[str, Any]) -> str | None:
+    """Classify RRG quadrant from RS-Ratio and RS-Momentum."""
+    rs_ratio = item.get("rs_ratio")
+    rs_momentum = item.get("rs_momentum")
+    if rs_ratio is None or rs_momentum is None:
+        return None
+    if rs_ratio > 100 and rs_momentum > 100:
+        return "Leading"
+    if rs_ratio > 100:
+        return "Weakening"
+    if rs_momentum <= 100:
+        return "Lagging"
+    return "Improving"
+
+
 async def get_cones(symbol: str, days: int = 365) -> dict[str, Any]:
     """Volatility Cones -- realized volatility quantiles for options analysis."""
     hist = await fetch_historical(symbol, days)