Add advanced setup guide and technical architecture

Author: Nitya-003

docs/SETUP_GUIDE.md

@@ -0,0 +1,25 @@
+# Advanced Setup & Technical Architecture
+
+## Docker Deployment
+### Using Docker Compose
+```yaml
+services:
+  bot:
+    build: .
+    env_file: .env
+    restart: always
+```
+Run with: `docker-compose up -d`
+
+## Database Management
+Eigen Bot uses **aiosqlite** for high-performance asynchronous operations.
+- `botdata.db`: Main storage for tickets and CodeBuddy.
+- `tags.db`: Dedicated tag storage.
+- `starboard.db`: Starboard message mapping.
+
+## Security
+- **Environment Variables:** Sensitive tokens are never hardcoded.
+- **Permission Checks:** Role-based access control (RBAC) ensures only authorized users can use Admin/Staff commands.
+- **Sanitization:** All user inputs are sanitized to prevent SQL injection.
+
+[← Back to README](../README.md)