chore: initial project scaffold with admin web, backend, desktop client, and deployment setup

Add monorepo structure for NexaVPN WireGuard control plane including:
- .gitignore for node_modules, build artifacts, and environment files
- README with project overview, monorepo layout, and quick start guide
- Admin web UI with React, Vite, TypeScript, and nginx reverse proxy
- API client with type definitions for users, devices, policies, gateways, and audit logs
- Admin pages for dashboard, users, devices, policies, g

backend/seed/001_seed.sql

@@ -0,0 +1,24 @@
+insert into roles (name, description)
+values
+    ('admin', 'NexaVPN administrator'),
+    ('user', 'Standard VPN user')
+on conflict (name) do nothing;
+
+insert into settings (category, key, value)
+values
+    ('vpn', 'default_dns_servers', '["10.20.0.53"]'::jsonb),
+    ('auth', 'access_token_ttl_seconds', '900'::jsonb),
+    ('auth', 'refresh_token_ttl_seconds', '2592000'::jsonb)
+on conflict (category, key) do nothing;
+
+insert into gateways (name, endpoint, public_key, listen_port, vpn_cidr, dns_servers, is_active)
+values (
+    'primary-gateway',
+    'vpn.example.com:51820',
+    'replace-me-with-gateway-public-key',
+    51820,
+    '100.96.0.0/24',
+    array['10.20.0.53'],
+    true
+)
+on conflict (name) do nothing;