refactor: address architect review findings (6 items)

R1: Extend @safe to catch ValueError->400, simplify routes_backtest
    (eliminated 4 copies of duplicated try/except)
R2: Consolidate PROVIDER constant into obb_utils.py (single source)
R3: Add days_ago() helper to obb_utils.py, replace 8+ duplications
R4: Extract Reddit/ApeWisdom into reddit_service.py from finnhub_service
R5: Fix missing top-level import asyncio in finnhub_service
R6: (deferred - sentiment logic extraction is a larger change)

All 561 tests passing.

market_service.py

@@ -7,12 +7,10 @@ from typing import Any
 
 from openbb import obb
 
-from obb_utils import to_list
+from obb_utils import to_list, days_ago, PROVIDER
 
 logger = logging.getLogger(__name__)
 
-PROVIDER = "yfinance"
-
 
 # --- ETF ---
 
@@ -30,7 +28,7 @@ async def get_etf_info(symbol: str) -> dict[str, Any]:
 
 async def get_etf_historical(symbol: str, days: int = 365) -> list[dict[str, Any]]:
     """Get ETF price history."""
-    start = (datetime.now(tz=timezone.utc) - timedelta(days=days)).strftime("%Y-%m-%d")
+    start = days_ago(days)
     try:
         result = await asyncio.to_thread(
             obb.etf.historical, symbol, start_date=start, provider=PROVIDER
@@ -66,7 +64,7 @@ async def get_available_indices() -> list[dict[str, Any]]:
 
 async def get_index_historical(symbol: str, days: int = 365) -> list[dict[str, Any]]:
     """Get index price history."""
-    start = (datetime.now(tz=timezone.utc) - timedelta(days=days)).strftime("%Y-%m-%d")
+    start = days_ago(days)
     try:
         result = await asyncio.to_thread(
             obb.index.price.historical, symbol, start_date=start, provider=PROVIDER
@@ -82,7 +80,7 @@ async def get_index_historical(symbol: str, days: int = 365) -> list[dict[str, A
 
 async def get_crypto_historical(symbol: str, days: int = 365) -> list[dict[str, Any]]:
     """Get cryptocurrency price history."""
-    start = (datetime.now(tz=timezone.utc) - timedelta(days=days)).strftime("%Y-%m-%d")
+    start = days_ago(days)
     try:
         result = await asyncio.to_thread(
             obb.crypto.price.historical, symbol, start_date=start, provider=PROVIDER
@@ -110,7 +108,7 @@ async def get_currency_historical(
     symbol: str, days: int = 365
 ) -> list[dict[str, Any]]:
     """Get forex price history (e.g., EURUSD)."""
-    start = (datetime.now(tz=timezone.utc) - timedelta(days=days)).strftime("%Y-%m-%d")
+    start = days_ago(days)
     try:
         result = await asyncio.to_thread(
             obb.currency.price.historical, symbol, start_date=start, provider=PROVIDER
@@ -140,7 +138,7 @@ async def get_futures_historical(
     symbol: str, days: int = 365
 ) -> list[dict[str, Any]]:
     """Get futures price history."""
-    start = (datetime.now(tz=timezone.utc) - timedelta(days=days)).strftime("%Y-%m-%d")
+    start = days_ago(days)
     try:
         result = await asyncio.to_thread(
             obb.derivatives.futures.historical, symbol, start_date=start, provider=PROVIDER