feat: add admin dashboard with usage stats

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/services/adminApi.ts

@@ -0,0 +1,61 @@
+import { apiJson } from './api.js'
+
+const ADMIN_BASE = '/api/admin'
+
+export interface AdminMe {
+  isAdmin: boolean
+  userId: string
+}
+
+export interface AdminSummary {
+  totalUsers: number
+  totalLogbooks: number
+  totalPhotos: number
+  totalVoiceMemos: number
+  totalGpsTracks: number
+  totalCollaborations: number
+  totalInvitations: number
+  aiSummaryEntries: number
+}
+
+export type AdminTimeBucket = 'day' | 'week' | 'month'
+
+export interface AdminTimeSeriesPoint {
+  date: string
+  count: number
+}
+
+export interface AdminTimeSeriesMetric {
+  metric: string
+  points: AdminTimeSeriesPoint[]
+}
+
+export interface AdminTimeSeriesResponse {
+  bucket: AdminTimeBucket
+  windowDays: number
+  series: AdminTimeSeriesMetric[]
+}
+
+export async function fetchAdminMe(): Promise<AdminMe> {
+  return await apiJson<AdminMe>(`${ADMIN_BASE}/me`)
+}
+
+export async function fetchAdminSummary(): Promise<AdminSummary> {
+  return await apiJson<AdminSummary>(`${ADMIN_BASE}/summary`)
+}
+
+export async function fetchAdminTimeSeries(
+  params: { bucket?: AdminTimeBucket; windowDays?: number } = {}
+): Promise<AdminTimeSeriesResponse> {
+  const search = new URLSearchParams()
+  if (params.bucket) {
+    search.set('bucket', params.bucket)
+  }
+  if (params.windowDays && Number.isFinite(params.windowDays)) {
+    search.set('window', String(params.windowDays))
+  }
+  const query = search.toString()
+  const url = query ? `${ADMIN_BASE}/timeseries?${query}` : `${ADMIN_BASE}/timeseries`
+  return await apiJson<AdminTimeSeriesResponse>(url)
+}
+