refactor(admin): split controls, training, control-provenance, iace/verification pages

Each page.tsx exceeded the 500-LOC hard cap. Extracted components and hooks into
colocated _components/ and _hooks/ directories; page.tsx is now a thin orchestrator.

- controls/page.tsx: 944 → 180 LOC; extracted ControlCard, AddControlForm,
  LoadingSkeleton, TransitionErrorBanner, StatsCards, FilterBar, RAGPanel into
  _components/ and useControlsData, useRAGSuggestions into _hooks/; types into _types.ts
- training/page.tsx: 780 → 288 LOC; extracted ContentTab (inline content generator tab)
  into _components/ContentTab.tsx
- control-provenance/page.tsx: 739 → 122 LOC; extracted MarkdownRenderer, UsageBadge,
  PermBadge, LicenseMatrix, SourceRegistry into _components/; PROVENANCE_SECTIONS
  static data into _data/provenance-sections.ts
- iace/[projectId]/verification/page.tsx: 673 → 196 LOC; extracted StatusBadge,
  VerificationForm, CompleteModal, SuggestEvidenceModal, VerificationTable into _components/

Zero behavior changes; logic relocated verbatim.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

admin-compliance/app/sdk/controls/_components/LoadingSkeleton.tsx

@@ -0,0 +1,18 @@
+export function LoadingSkeleton() {
+  return (
+    <div className="space-y-4">
+      {[1, 2, 3].map(i => (
+        <div key={i} className="bg-white rounded-xl border border-gray-200 p-6 animate-pulse">
+          <div className="flex items-center gap-2 mb-3">
+            <div className="h-5 w-20 bg-gray-200 rounded" />
+            <div className="h-5 w-16 bg-gray-200 rounded-full" />
+            <div className="h-5 w-16 bg-gray-200 rounded-full" />
+          </div>
+          <div className="h-6 w-3/4 bg-gray-200 rounded mb-2" />
+          <div className="h-4 w-full bg-gray-100 rounded" />
+          <div className="mt-4 h-2 bg-gray-200 rounded-full" />
+        </div>
+      ))}
+    </div>
+  )
+}