krakenfutures: add funding_fee_candle_limit for limited history

Kraken Futures retains only ~29 days of hourly funding rate history.
Set funding_fee_candle_limit to 700 so ohlcv_candle_limit returns the
correct cap for CandleType.FUNDING_RATE instead of the general OHLCV
limit.

freqtrade/exchange/krakenfutures.py

@@ -51,6 +51,8 @@ class Krakenfutures(Exchange):
             PriceType.MARK: "mark",
             PriceType.INDEX: "index",
         },
+        # Kraken Futures retains only 29 days of hourly funding rate history.
+        "funding_fee_candle_limit": 700,
     }
 
     @retrier

tests/exchange/test_krakenfutures.py

@@ -32,6 +32,8 @@ def test_krakenfutures_ft_has_overrides():
     assert ft_has["stoploss_query_requires_stop_flag"] is True
     assert ft_has["stop_price_param"] == "triggerPrice"
     assert ft_has["stop_price_type_field"] == "triggerSignal"
+    # Kraken retains only ~29 days of hourly funding rate history
+    assert ft_has["funding_fee_candle_limit"] == 700
 
 
 def test_krakenfutures_ohlcv_candle_limit_uses_ccxt_limit(mocker, default_conf):
@@ -44,6 +46,15 @@ def test_krakenfutures_ohlcv_candle_limit_uses_ccxt_limit(mocker, default_conf):
     assert ex.ohlcv_candle_limit("1m", candle_type=CandleType.FUTURES) == 2000
 
 
+def test_krakenfutures_ohlcv_candle_limit_funding_rate(mocker, default_conf):
+    """Funding rate candle limit is capped to reflect Kraken's limited history retention."""
+    ex = get_patched_exchange(mocker, default_conf, exchange="krakenfutures")
+
+    mocker.patch.object(ex, "features", return_value=2000)
+
+    assert ex.ohlcv_candle_limit("1h", candle_type=CandleType.FUNDING_RATE) == 700
+
+
 # --- fetch_order fallback tests ---