feat(09-02): create AdminOverviewView.vue

- Single-fetch view calling getAdminOverview() on mount with loading/error states
- Four stat cards grid (Users, Storage, Processing, Ready) per ADMIN-11 and D-01
- Recent audit table with 5 columns (When/Event/Actor/Target/IP) matching AuditLogTab.vue structure
- Uses formatSize/formatDate from shared utils/formatters.js (no duplication)
- No top-level padding (AdminLayout owns p-8 max-w-5xl mx-auto)
- No Pinia store — single-fetch component consistent with admin tab pattern

frontend/src/views/admin/AdminOverviewView.vue

@@ -0,0 +1,98 @@
+<template>
+  <div>
+    <h2 class="text-xl font-semibold text-gray-900 mb-6">Overview</h2>
+
+    <!-- Loading -->
+    <div v-if="loading" class="text-gray-500">Loading overview…</div>
+
+    <!-- Error -->
+    <div v-else-if="error" class="text-red-600">{{ error }}</div>
+
+    <!-- Content -->
+    <template v-else-if="overview">
+      <!-- Stat cards -->
+      <div class="grid grid-cols-1 md:grid-cols-4 gap-4 mb-8">
+        <!-- Users -->
+        <div class="bg-white border border-gray-200 rounded-xl p-6">
+          <p class="text-xs font-semibold text-gray-400 uppercase tracking-wider mb-1">Users</p>
+          <p class="text-2xl font-bold text-gray-900">{{ overview.user_count }}</p>
+        </div>
+
+        <!-- Storage -->
+        <div class="bg-white border border-gray-200 rounded-xl p-6">
+          <p class="text-xs font-semibold text-gray-400 uppercase tracking-wider mb-1">Storage</p>
+          <p class="text-2xl font-bold text-gray-900">{{ formatSize(overview.total_storage_bytes) }}</p>
+        </div>
+
+        <!-- Processing -->
+        <div class="bg-white border border-gray-200 rounded-xl p-6">
+          <p class="text-xs font-semibold text-gray-400 uppercase tracking-wider mb-1">Processing</p>
+          <p class="text-2xl font-bold text-gray-900">{{ overview.doc_status?.processing ?? 0 }}</p>
+        </div>
+
+        <!-- Ready -->
+        <div class="bg-white border border-gray-200 rounded-xl p-6">
+          <p class="text-xs font-semibold text-gray-400 uppercase tracking-wider mb-1">Ready</p>
+          <p class="text-2xl font-bold text-gray-900">{{ overview.doc_status?.ready ?? 0 }}</p>
+        </div>
+      </div>
+
+      <!-- Recent audit table -->
+      <div>
+        <h3 class="text-sm font-semibold text-gray-700 mb-3">Recent Activity</h3>
+
+        <div v-if="overview.recent_audit && overview.recent_audit.length === 0" class="text-sm text-gray-400 italic">
+          No recent activity
+        </div>
+
+        <div v-else class="bg-white rounded-xl border border-gray-200 overflow-hidden">
+          <table class="w-full text-sm border-collapse">
+            <thead>
+              <tr class="bg-gray-50 border-b border-gray-200">
+                <th scope="col" class="px-4 py-3 text-left text-xs font-semibold text-gray-400 uppercase tracking-wider">When</th>
+                <th scope="col" class="px-4 py-3 text-left text-xs font-semibold text-gray-400 uppercase tracking-wider">Event</th>
+                <th scope="col" class="px-4 py-3 text-left text-xs font-semibold text-gray-400 uppercase tracking-wider">Actor</th>
+                <th scope="col" class="px-4 py-3 text-left text-xs font-semibold text-gray-400 uppercase tracking-wider">Target</th>
+                <th scope="col" class="px-4 py-3 text-left text-xs font-semibold text-gray-400 uppercase tracking-wider">IP</th>
+              </tr>
+            </thead>
+            <tbody>
+              <tr
+                v-for="entry in overview.recent_audit"
+                :key="entry.id"
+                class="border-b border-gray-100 hover:bg-gray-50 transition-colors"
+              >
+                <td class="px-4 py-3 font-mono text-xs text-gray-500">{{ formatDate(entry.created_at) }}</td>
+                <td class="px-4 py-3 text-sm text-gray-700">{{ entry.event_type }}</td>
+                <td class="px-4 py-3 text-sm text-gray-700">{{ entry.owner_handle ?? '—' }}</td>
+                <td class="px-4 py-3 text-sm text-gray-500">{{ entry.target_user_handle ?? '—' }}</td>
+                <td class="px-4 py-3 font-mono text-xs text-gray-700">{{ entry.ip_address ?? '—' }}</td>
+              </tr>
+            </tbody>
+          </table>
+        </div>
+      </div>
+    </template>
+  </div>
+</template>
+
+<script setup>
+import { ref, onMounted } from 'vue'
+import { getAdminOverview } from '../../api/admin.js'
+import { formatSize, formatDate } from '../../utils/formatters.js'
+
+const loading = ref(false)
+const error = ref(null)
+const overview = ref(null)
+
+onMounted(async () => {
+  loading.value = true
+  try {
+    overview.value = await getAdminOverview()
+  } catch (e) {
+    error.value = e?.message || 'Failed to load overview'
+  } finally {
+    loading.value = false
+  }
+})
+</script>