feat: add 67 new endpoints across 10 feature groups

Prerequisite refactor:
- Consolidate duplicate _to_dicts into shared obb_utils.to_list
- Add fetch_historical and first_or_empty helpers to obb_utils

Phase 1 - Local computation (no provider risk):
- Group I: 12 technical indicators (ATR, ADX, Stoch, OBV, Ichimoku,
  Donchian, Aroon, CCI, Keltner, Fibonacci, A/D, Volatility Cones)
- Group J: Sortino, Omega ratios + rolling stats (variance, stdev,
  mean, skew, kurtosis, quantile via generic endpoint)
- Group H: ECB currency reference rates

Phase 2 - FRED/Federal Reserve providers:
- Group C: 10 fixed income endpoints (treasury rates, yield curve,
  auctions, TIPS, EFFR, SOFR, HQM, commercial paper, spot rates,
  spreads)
- Group D: 11 economy endpoints (CPI, GDP, unemployment, PCE, money
  measures, CLI, HPI, FRED search, balance of payments, Fed holdings,
  FOMC documents)
- Group E: 5 survey endpoints (Michigan, SLOOS, NFP, Empire State,
  BLS search)

Phase 3 - SEC/stockgrid/FINRA providers:
- Group B: 4 equity fundamental endpoints (management, dividends,
  SEC filings, company search)
- Group A: 4 shorts/dark pool endpoints (short volume, FTD, short
  interest, OTC dark pool)
- Group F: 3 index/ETF enhanced (S&P 500 multiples, index
  constituents, ETF N-PORT)

Phase 4 - Regulators:
- Group G: 5 regulatory endpoints (COT report, COT search, SEC
  litigation, institution search, CIK mapping)

Security hardening:
- Service-layer allowlists for all getattr dynamic dispatch
- Regex validation on date, country, security_type, form_type params
- Exception handling in fetch_historical
- Callable guard on rolling stat dispatch

Total: 32 existing + 67 new = 99 endpoints, all free providers.

obb_utils.py

@@ -1,7 +1,16 @@
 """Shared OpenBB result conversion utilities."""
 
+import asyncio
+import logging
+from datetime import datetime, timedelta, timezone
 from typing import Any
 
+from openbb import obb
+
+logger = logging.getLogger(__name__)
+
+PROVIDER = "yfinance"
+
 
 def to_list(result: Any) -> list[dict[str, Any]]:
     """Convert OBBject result to list of dicts with serialized dates."""
@@ -49,3 +58,26 @@ def safe_last(result: Any) -> dict[str, Any] | None:
         return None
     last = items[-1]
     return last.model_dump() if hasattr(last, "model_dump") else None
+
+
+def first_or_empty(result: Any) -> dict[str, Any]:
+    """Get first result as dict, or empty dict."""
+    items = to_list(result)
+    return items[0] if items else {}
+
+
+async def fetch_historical(
+    symbol: str, days: int = 365, provider: str = PROVIDER,
+) -> Any | None:
+    """Fetch historical price data, returning the OBBject result or None."""
+    start = (datetime.now(tz=timezone.utc) - timedelta(days=days)).strftime("%Y-%m-%d")
+    try:
+        result = await asyncio.to_thread(
+            obb.equity.price.historical, symbol, start_date=start, provider=provider,
+        )
+    except Exception:
+        logger.warning("Historical fetch failed for %s", symbol, exc_info=True)
+        return None
+    if result is None or result.results is None:
+        return None
+    return result