fix(mc-browser): scope fallback + severity/domain filters

- Add scope/risk_score/implementation_effort fallbacks to prevent
  'undefined is not an object' crash in ControlDetail
- Add severity filter (high/medium/low based on total_controls)
- Add domain filter (L1 token prefix match)
- Fix sort options (source → canonical_name)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

admin-compliance/app/sdk/master-controls/page.tsx

@@ -35,11 +35,22 @@ export default function MasterControlsPage() {
     )
   }
 
-  // DETAIL mode
+  // DETAIL mode — add fallback fields that ControlDetail expects
   if (state.mode === 'detail' && state.selectedControl) {
+    const safeCtrl = {
+      ...state.selectedControl,
+      scope: state.selectedControl.scope || { platforms: [], components: [], data_classes: [] },
+      target_audience: state.selectedControl.target_audience || [],
+      requirements: state.selectedControl.requirements || [],
+      test_procedure: state.selectedControl.test_procedure || [],
+      evidence: state.selectedControl.evidence || [],
+      open_anchors: state.selectedControl.open_anchors || [],
+      risk_score: state.selectedControl.risk_score || null,
+      implementation_effort: state.selectedControl.implementation_effort || null,
+    }
     return (
       <ControlDetail
-        ctrl={state.selectedControl}
+        ctrl={safeCtrl}
         onBack={() => { state.setMode('list'); state.setSelectedControl(null) }}
         onEdit={() => {}}
         onDelete={async () => {}}