fix(hub): stop instance iframe nav flash after account status badge

Load account_risk_badge.css before body paint, skip redundant hub theme re-apply, remove iframe hide overlay, and disable badge transitions in hub embed.

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

static/account_risk_badge.css

@@ -68,6 +68,11 @@ html[data-theme="light"] {
   transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
 }
 
+/* 中控 iframe 内切页：避免徽章过渡动画造成 header 闪动 */
+html[data-hub-linked="1"] .header-row .risk-status-badge {
+  transition: none;
+}
+
 .risk-status-badge::before {
   content: "";
   width: 7px;