fix(hub): 修复行情区 K 线 Gate 分页与图表 unexpected base

Gate OHLCV 分页在接近当前时间时停止并容错 from>to；分页失败时用 limit 兜底。chart.js 为 priceFormat 增加整数 base，setData 失败时回退默认精度。

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

hub_ohlcv_lib.py

@@ -275,18 +275,33 @@ def _paginate_fetch_ohlcv(
     else:
         since = max(0, int(time.time() * 1000) - want * period_ms)
 
+    now_ms = int(time.time() * 1000)
     guard = 0
     prev_since = None
     while len(collected) < want and guard < 80:
         guard += 1
+        if since >= now_ms:
+            break
         req_limit = min(chunk_max, want - len(collected))
-        batch = exchange.fetch_ohlcv(
-            ex_sym, timeframe=tf, since=since, limit=req_limit
-        )
+        try:
+            batch = exchange.fetch_ohlcv(
+                ex_sym, timeframe=tf, since=since, limit=req_limit
+            )
+        except Exception as e:
+            err = str(e).lower()
+            if collected and (
+                "from" in err
+                and "to" in err
+                or "invalid request parameter" in err
+            ):
+                break
+            raise
         if not batch:
             break
         collected.extend(batch)
         next_since = _next_since_from_batch(batch, period_ms)
+        if next_since >= now_ms:
+            break
         if prev_since is not None and next_since <= prev_since:
             break
         prev_since = since
@@ -385,6 +400,16 @@ def fetch_ohlcv_for_hub(
             if len(merged) > want:
                 merged = merged[-want:]
 
+        if not merged:
+            try:
+                tail = exchange.fetch_ohlcv(
+                    ex_sym, timeframe=tf, limit=min(want, 300)
+                )
+                merged = _bars_to_dicts(tail or [])
+                if len(merged) > want:
+                    merged = merged[-want:]
+            except Exception:
+                pass
         if not merged:
             return {"ok": False, "msg": "交易所未返回 K 线"}