Update dashboard community links to use env vars, add deploy configs

- Dashboard community links now use .env values like community page
- Removed hardcoded social media URLs from dashboard
- Added deploy folder with nginx and systemd service configs
- Moved linktree page to public route
- Various backend and auth context updates

deploy/spanglish-backend.service

@@ -0,0 +1,29 @@
+[Unit]
+Description=Spanglish Backend API
+Documentation=https://github.com/spanglish/Spanglish
+After=network.target
+
+[Service]
+Type=simple
+User=spanglish
+Group=spanglish
+WorkingDirectory=/home/spanglish/Spanglish/backend
+Environment=NODE_ENV=production
+Environment=PORT=3018
+EnvironmentFile=/home/spanglish/Spanglish/backend/.env
+ExecStart=/usr/bin/node dist/index.js
+Restart=on-failure
+RestartSec=10
+StandardOutput=syslog
+StandardError=syslog
+SyslogIdentifier=spanglish-backend
+
+# Security hardening
+NoNewPrivileges=true
+PrivateTmp=true
+ProtectSystem=strict
+ProtectHome=read-only
+ReadWritePaths=/home/spanglish/Spanglish/backend/uploads /home/spanglish/Spanglish/backend/data
+
+[Install]
+WantedBy=multi-user.target