Fix CCP Metrics page crash for non-Admin users

CCPMetricsPage called isEditor() which does not exist in AuthContext.
Admin users were unaffected due to JS short-circuit evaluation on
isAdmin() || isEditor(). Standard_User accounts hit TypeError because
isEditor was undefined.

Replaced isEditor() with canWrite() which is the correct auth helper
for write-capable users (Admin + Standard_User).

Closes #15

frontend/src/components/pages/CCPMetricsPage.js

@@ -1012,7 +1012,7 @@ function DataManagementPanel({ onClose, onDataChanged }) {
 // Main Page Component
 // ---------------------------------------------------------------------------
 export default function CCPMetricsPage() {
-    const { isAdmin, isEditor } = useAuth();
+    const { isAdmin, canWrite } = useAuth();
     const [stats, setStats] = useState(null);
     const [trend, setTrend] = useState(null);
     const [burndownData, setBurndownData] = useState(null);
@@ -1115,7 +1115,7 @@ export default function CCPMetricsPage() {
                         Cross-organizational compliance posture across all verticals
                     </p>
                 </div>
-                {(isAdmin() || isEditor()) && (
+                {canWrite() && (
                     <div style={{ display: 'flex', gap: '0.75rem' }}>
                         {isAdmin() && (
                             <button
@@ -1227,7 +1227,7 @@ export default function CCPMetricsPage() {
                     <div style={{ fontSize: '0.75rem', color: '#64748B', marginBottom: '1.5rem' }}>
                         Upload per-vertical compliance xlsx files to generate cross-organizational reports.
                     </div>
-                    {(isAdmin() || isEditor()) && (
+                    {canWrite() && (
                         <button
                             onClick={() => setShowUpload(true)}
                             style={{