Use hub exchange instances for calculator contract precision.

Load enabled instances from settings, fetch market info via /api/hub/market, and apply exchange-specific amount and price precision in trend and roll calculators.

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

hub_bridge.py

@@ -214,6 +214,7 @@ def install_on_app(
     ohlcv_fn=None,
     account_fn=None,
     volume_rank_fn=None,
+    market_fn=None,
     reconcile_hub_flat_fn=None,
     risk_status_fn=None,
     user_close_fn=None,
@@ -229,6 +230,7 @@ def install_on_app(
         "views": views,
         "ohlcv_fn": ohlcv_fn,
         "volume_rank_fn": volume_rank_fn,
+        "market_fn": market_fn,
         "reconcile_hub_flat_fn": reconcile_hub_flat_fn,
         "risk_status_fn": risk_status_fn,
         "user_close_fn": user_close_fn,
@@ -602,6 +604,21 @@ def register_hub_routes(app):
         except Exception as e:
             return jsonify({"ok": False, "msg": str(e)}), 500
 
+    @app.route("/api/hub/market")
+    @_hub_auth_required
+    def api_hub_market():
+        fn = _ctx().get("market_fn")
+        if not callable(fn):
+            return jsonify({"ok": False, "msg": "该实例未配置合约信息接口"}), 501
+        base = (request.args.get("base") or request.args.get("symbol") or "").strip()
+        try:
+            result = fn(base=base)
+            if isinstance(result, dict):
+                return jsonify(result)
+            return jsonify({"ok": False, "msg": "合约信息返回格式无效"}), 500
+        except Exception as e:
+            return jsonify({"ok": False, "msg": str(e)}), 500
+
     @app.route("/api/hub/ohlcv")
     @_hub_auth_required
     def api_hub_ohlcv():