Add comprehensive demo data loading logic and .env.demo configuration

- Implemented `load_demo_data` to populate organizations, users, and relationships from `demo_data.json`.
- Refactored database initialization to handle demo-specific passwords and multi-entity creation in demo mode.
- Added `demo_data.json` with sample organizations and users for better demo showcase.
- Introduced `.env.demo` to simplify environment setup for demo scenarios.
- Updated `.gitignore` to include `.env.demo` while keeping other `.env` files excluded.

frontend/src/lib/api/admin.ts

@@ -0,0 +1,45 @@
+import { apiClient } from './client';
+import type { Options } from './generated/sdk.gen';
+
+export interface UserGrowthData {
+    date: string;
+    totalUsers: number;
+    activeUsers: number;
+}
+
+export interface OrgDistributionData {
+    name: string;
+    value: number;
+}
+
+export interface UserStatusData {
+    name: string;
+    value: number;
+}
+
+export interface AdminStatsResponse {
+    user_growth: UserGrowthData[];
+    organization_distribution: OrgDistributionData[];
+    user_status: UserStatusData[];
+}
+
+/**
+ * Admin: Get Dashboard Stats
+ *
+ * Get aggregated statistics for the admin dashboard (admin only)
+ */
+export const getAdminStats = <ThrowOnError extends boolean = false>(
+    options?: Options<any, ThrowOnError>
+) => {
+    return (options?.client ?? apiClient).get<AdminStatsResponse, any, ThrowOnError>({
+        responseType: 'json',
+        security: [
+            {
+                scheme: 'bearer',
+                type: 'http',
+            },
+        ],
+        url: '/api/v1/admin/stats',
+        ...options,
+    });
+};