Skip exchange PnL sync on hub iframe soft nav to fix slow records tab.

Remove hover prefetch and mark soft-nav fetches so Gate/OKX render pages from local DB without blocking on exchange history sync.

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

tests/test_instance_nav_lib.py

@@ -0,0 +1,21 @@
+from instance_nav_lib import request_is_hub_soft_nav
+
+
+def test_request_is_hub_soft_nav():
+    class Req:
+        args = {"embed": "1"}
+        headers = {"X-Instance-Soft-Nav": "1"}
+
+    assert request_is_hub_soft_nav(Req()) is True
+
+    class Req2:
+        args = {"embed": "1"}
+        headers = {}
+
+    assert request_is_hub_soft_nav(Req2()) is False
+
+    class Req3:
+        args = {}
+        headers = {"X-Instance-Soft-Nav": "1"}
+
+    assert request_is_hub_soft_nav(Req3()) is False