feat: Integrate Electric SQL for real-time notifications and enhance PostgreSQL configuration

- Added Electric SQL service to docker-compose for real-time data synchronization.
- Introduced PostgreSQL configuration for logical replication and performance tuning.
- Created scripts for initializing Electric SQL user and electrifying tables.
- Implemented notification model and service in the backend.
- Developed ElectricProvider and useNotifications hook in the frontend for managing notifications.
- Updated environment variables and package dependencies for Electric SQL integration.

surfsense_web/.env.example

@@ -1,5 +1,10 @@
 NEXT_PUBLIC_FASTAPI_BACKEND_URL=http://localhost:8000
 NEXT_PUBLIC_FASTAPI_BACKEND_AUTH_TYPE=LOCAL or GOOGLE
 NEXT_PUBLIC_ETL_SERVICE=UNSTRUCTURED or LLAMACLOUD or DOCLING
+
+# Electric SQL
+NEXT_PUBLIC_ELECTRIC_URL=http://localhost:5133
+NEXT_PUBLIC_ELECTRIC_AUTH_MODE=insecure
+
 # Contact Form Vars - OPTIONAL
 DATABASE_URL=postgresql://postgres:[YOUR-PASSWORD]@db.sdsf.supabase.co:5432/postgres