docs: add root .env.example with DATABASE_URL and NEXT_PUBLIC_API_URL

Author: DHANUSHGCODE

.env.example

@@ -0,0 +1,36 @@
+# ============================================================
+# AI-Powered Security Monitoring & Threat Detection Platform
+# Root .env.example - copy to .env and fill in your values
+# ============================================================
+
+# --------------------------
+# Backend (FastAPI)
+# --------------------------
+
+# SQLite (default for local dev - no changes needed)
+DATABASE_URL=sqlite:///./security_logs.db
+
+# PostgreSQL (for production - uncomment and set values)
+# DATABASE_URL=postgresql://user:password@localhost:5432/security_db
+
+# --------------------------
+# Frontend (Next.js)
+# --------------------------
+
+# URL of the FastAPI backend that the Next.js dashboard connects to
+# For local dev:
+NEXT_PUBLIC_API_URL=http://localhost:8000
+
+# For Docker Compose:
+# NEXT_PUBLIC_API_URL=http://backend:8000
+
+# For production:
+# NEXT_PUBLIC_API_URL=https://your-api-domain.com
+
+# --------------------------
+# Docker Compose (optional)
+# --------------------------
+
+# Override ports if needed
+# BACKEND_PORT=8000
+# FRONTEND_PORT=3000