Fix header funds flicker and unify settings page top bar.

Preserve SSR fund values when account_snapshot returns null, retry on failure, and show the same instance header panel on system settings.

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

lib/instance/templates/settings_panel.html

@@ -1,18 +1,5 @@
-{# 系统设置：左风控说明 · 右资金划转 + 数据导出 #}
+{# 系统设置：左风控说明 · 右资金划转 + 数据导出（顶栏资金与统计见 instance_header_panel） #}
 <div class="settings-page">
-    <div class="card settings-account-summary">
-        <div class="settings-account-summary-head">
-            <div class="instance-toolbar-status">
-                <div class="exchange-tag">{{ exchange_display }}</div>
-                <span class="risk-status-badge risk-status-{{ risk_status.status|default('normal') }}" role="status">{{ risk_status.status_label|default('正常') }}</span>
-            </div>
-            <div class="settings-account-summary-actions">
-                {% include 'instance_theme_toggle.html' %}
-                <button type="button" class="btn-secondary btn-sm" id="settings-refresh-funds">刷新资金</button>
-            </div>
-        </div>
-        {% include 'instance_header_stats.html' %}
-    </div>
     <div class="settings-cards-grid">
         <div class="card settings-card settings-card--risk">
             <h2>风控说明</h2>