frontend error management enhancement

app/templates/admin/errors/502.html

@@ -0,0 +1,44 @@
+{% extends "admin/errors/base.html" %}
+
+{% block icon %}🔌{% endblock %}
+
+{% block title %}502 - Bad Gateway{% endblock %}
+
+{% block content %}
+<div class="error-icon">🔌</div>
+<div class="status-code">502</div>
+<div class="status-name">Bad Gateway</div>
+<div class="error-message">
+    We're unable to reach the service right now. This is usually temporary. Please try again in a moment.
+</div>
+<div class="error-code">Error Code: {{ error_code }}</div>
+
+<div class="action-buttons">
+    <a href="javascript:location.reload()" class="btn btn-primary">Retry</a>
+    <a href="/admin/dashboard" class="btn btn-secondary">Dashboard</a>
+</div>
+
+{% if show_debug %}
+<div class="debug-info">
+    <h3>🔧 Debug Information (Admin Only)</h3>
+    <div class="debug-item">
+        <span class="debug-label">Path:</span>
+        <span class="debug-value">{{ path }}</span>
+    </div>
+    <div class="debug-item">
+        <span class="debug-label">Error Code:</span>
+        <span class="debug-value">{{ error_code }}</span>
+    </div>
+    {% if details %}
+    <div class="debug-item">
+        <span class="debug-label">Details:</span>
+        <pre>{{ details | tojson(indent=2) }}</pre>
+    </div>
+    {% endif %}
+</div>
+{% endif %}
+
+<div class="support-link">
+    Service unavailable for extended period? <a href="/admin/support">Check Status</a>
+</div>
+{% endblock %}