fix(options): speed up chain refresh with fast path and non-blocking UI

Skip full REST tickers when WS is warm, seed subscriptions off-request, and keep the old chain visible while refreshing.

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

lib/options/options_quote_live_lib.py

@@ -158,7 +158,58 @@ class OptionsQuoteLive:
         args = [{"channel": "tickers", "instId": iid} for iid in merged]
         for iid in sorted(index_insts):
             args.append({"channel": "index-tickers", "instId": iid})
-        self._ws.set_subscriptions(args)
+        # 订阅可能分片 sleep,不能堵 Flask 请求线程
+        threading.Thread(
+            target=self._ws.set_subscriptions,
+            args=(args,),
+            name="okx-options-quote-sub",
+            daemon=True,
+        ).start()
+
+    def as_okx_tickers(self, underlying: str | None = None) -> dict[str, dict[str, Any]]:
+        """转成 build_option_chain 可用的 OKX ticker 字段."""
+        u = (underlying or "").upper()
+        out: dict[str, dict[str, Any]] = {}
+        with self._lock:
+            for inst_id, q in self._tickers.items():
+                if u and str(q.get("underlying") or "").upper() not in ("", u):
+                    continue
+                row: dict[str, Any] = {"instId": inst_id}
+                if q.get("ask") is not None and not q.get("ask_estimated"):
+                    row["askPx"] = q.get("ask")
+                    row["askSz"] = q.get("ask_sz")
+                if q.get("bid") is not None:
+                    row["bidPx"] = q.get("bid")
+                    row["bidSz"] = q.get("bid_sz")
+                if q.get("mark_px") is not None:
+                    row["markPx"] = q.get("mark_px")
+                out[inst_id] = row
+        return out
+
+    def index_px_for(self, underlying: str) -> float | None:
+        u = (underlying or "").upper()
+        with self._lock:
+            return self._index_by_uly.get(u)
+
+    def is_ws_fresh(self, *, max_age_sec: float = 15.0) -> bool:
+        if not self._ws.connected:
+            return False
+        last = float(self._ws.last_msg_at or 0)
+        return last > 0 and (time.time() - last) <= max_age_sec
+
+    def schedule_seed_from_chain(
+        self,
+        chain: dict[str, Any],
+        *,
+        exp_time: str | int | None = None,
+        watcher_id: str | None = None,
+    ) -> None:
+        threading.Thread(
+            target=self.seed_from_chain,
+            kwargs={"chain": chain, "exp_time": exp_time, "watcher_id": watcher_id},
+            name="options-quote-seed",
+            daemon=True,
+        ).start()
 
     def seed_from_chain(
         self,