Isolate CTP in worker process and improve strategy roll UX.

Split vn.py into qihuo-ctp worker with IPC client bridge, keep CTP connected during breaks with cached account fallback, speed up strategy page loads, and allow off-session breakout roll submissions.

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

dashboard_lib.py

@@ -175,6 +175,18 @@ def build_dashboard_payload(
                     margin_used = round(max(0.0, equity - available), 2)
             except Exception:
                 pass
+        else:
+            from trading_context import _cached_ctp_account
+
+            cached = _cached_ctp_account(mode)
+            balance = float(cached.get("balance") or 0)
+            if balance > 0:
+                equity = balance
+            avail = cached.get("available")
+            if avail is not None:
+                available = round(float(avail), 2)
+                if equity > 0:
+                    margin_used = round(max(0.0, equity - available), 2)
 
         key_rows = conn.execute(
             """