Add clear-and-refetch for hub K-line cache.

Force refresh wipes the series in hub_kline.db before pulling from the exchange; add a Linux clear script and rename the UI button to 清库重拉.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_hub_kline_store.py

@@ -7,6 +7,7 @@ import unittest
 from pathlib import Path
 
 from hub_kline_store import (
+    clear_series_bars,
     init_db,
     load_bars_before,
     load_bars_latest,
@@ -339,6 +340,57 @@ class TestHubKlineStore(unittest.TestCase):
         self.assertGreaterEqual(len(out.get("candles") or []), 100)
         self.assertGreater(int(out.get("fetched") or 0), 0)
 
+    def test_clear_series_and_force_refetch(self):
+        init_db(self.db)
+        period = TIMEFRAME_MS["5m"]
+        now = int(time.time() * 1000)
+        stale = [
+            {
+                "open_time_ms": now - period * (i + 100),
+                "open": 1,
+                "high": 2,
+                "low": 0.5,
+                "close": 1.5,
+                "volume": 1,
+            }
+            for i in range(40)
+        ]
+        upsert_bars("binance", "BTC/USDT", "5m", stale, self.db)
+        self.assertEqual(len(load_bars_latest("binance", "BTC/USDT", "5m", 100, self.db)), 40)
+        removed = clear_series_bars("binance", "BTC/USDT", "5m", self.db)
+        self.assertEqual(removed, 40)
+        self.assertEqual(len(load_bars_latest("binance", "BTC/USDT", "5m", 100, self.db)), 0)
+
+        fresh = [
+            {
+                "open_time_ms": now - period * (20 - i),
+                "open": 10,
+                "high": 11,
+                "low": 9,
+                "close": 10.5,
+                "volume": 2,
+            }
+            for i in range(20)
+        ]
+
+        def remote_fetch(**kwargs):
+            return {"ok": True, "bars": fresh, "price_tick": 0.01}
+
+        out = resolve_chart_bars(
+            "binance",
+            "BTC/USDT",
+            "5m",
+            remote_fetch,
+            db_path=self.db,
+            force_refresh=True,
+            clear_db=True,
+            limit=50,
+        )
+        self.assertTrue(out.get("ok"))
+        self.assertGreaterEqual(int(out.get("cleared") or 0), 0)
+        self.assertGreater(int(out.get("fetched") or 0), 0)
+        self.assertGreaterEqual(len(out.get("candles") or []), 19)
+
     def test_resolve_before_ms_exhausted(self):
         init_db(self.db)