refactor(admin): split dsr page.tsx into colocated components

Extract TabNavigation, StatCard, RequestCard, FilterBar, DSRCreateModal,
DSRDetailPanel, DSRHeaderActions, and banner components (LoadingSpinner,
SettingsTab, OverdueAlert, DeadlineInfoBox, EmptyState) into _components/
so page.tsx drops from 1019 to 247 LOC (under the 300 soft target).

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

admin-compliance/app/sdk/dsr/_components/TabNavigation.tsx

@@ -0,0 +1,45 @@
+'use client'
+
+import type { Tab, TabId } from '../_types'
+
+export function TabNavigation({
+  tabs,
+  activeTab,
+  onTabChange
+}: {
+  tabs: Tab[]
+  activeTab: TabId
+  onTabChange: (tab: TabId) => void
+}) {
+  return (
+    <div className="border-b border-gray-200">
+      <nav className="flex gap-1 -mb-px" aria-label="Tabs">
+        {tabs.map(tab => (
+          <button
+            key={tab.id}
+            onClick={() => onTabChange(tab.id)}
+            className={`
+              px-4 py-3 text-sm font-medium border-b-2 transition-colors
+              ${activeTab === tab.id
+                ? 'border-purple-600 text-purple-600'
+                : 'border-transparent text-gray-500 hover:text-gray-700 hover:border-gray-300'
+              }
+            `}
+          >
+            <span className="flex items-center gap-2">
+              {tab.label}
+              {tab.count !== undefined && tab.count > 0 && (
+                <span className={`
+                  px-2 py-0.5 text-xs rounded-full
+                  ${tab.countColor || 'bg-gray-100 text-gray-600'}
+                `}>
+                  {tab.count}
+                </span>
+              )}
+            </span>
+          </button>
+        ))}
+      </nav>
+    </div>
+  )
+}