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_backend/alembic/versions/60_add_notifications_table.py

@@ -0,0 +1,51 @@
+"""Add notifications table
+
+Revision ID: 60
+Revises: 59
+"""
+from collections.abc import Sequence
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "60"
+down_revision: str | None = "59"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    """Upgrade schema - add notifications table."""
+    # Create notifications table
+    op.execute(
+        """
+        CREATE TABLE IF NOT EXISTS notifications (
+            id SERIAL PRIMARY KEY,
+            user_id UUID NOT NULL REFERENCES "user"(id) ON DELETE CASCADE,
+            search_space_id INTEGER REFERENCES searchspaces(id) ON DELETE CASCADE,
+            type VARCHAR(50) NOT NULL,
+            title VARCHAR(200) NOT NULL,
+            message TEXT NOT NULL,
+            read BOOLEAN NOT NULL DEFAULT FALSE,
+            metadata JSONB DEFAULT '{}',
+            created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+            updated_at TIMESTAMPTZ
+        );
+    """
+    )
+
+    # Create indexes
+    op.create_index("ix_notifications_user_id", "notifications", ["user_id"])
+    op.create_index("ix_notifications_read", "notifications", ["read"])
+    op.create_index("ix_notifications_created_at", "notifications", ["created_at"])
+    op.create_index("ix_notifications_user_read", "notifications", ["user_id", "read"])
+
+
+def downgrade() -> None:
+    """Downgrade schema - remove notifications table."""
+    op.drop_index("ix_notifications_user_read", table_name="notifications")
+    op.drop_index("ix_notifications_created_at", table_name="notifications")
+    op.drop_index("ix_notifications_read", table_name="notifications")
+    op.drop_index("ix_notifications_user_id", table_name="notifications")
+    op.drop_table("notifications")
+