fix(db): more labels migrations

migrations/20240620000002_add_assigned_by_to_document_labels.sql

@@ -0,0 +1,9 @@
+-- Add assigned_by column to document_labels table
+ALTER TABLE document_labels ADD COLUMN assigned_by UUID REFERENCES users(id) ON DELETE SET NULL;
+
+-- Add assigned_by column to source_labels table for consistency
+ALTER TABLE source_labels ADD COLUMN assigned_by UUID REFERENCES users(id) ON DELETE SET NULL;
+
+-- Add indexes for performance
+CREATE INDEX idx_document_labels_assigned_by ON document_labels(assigned_by);
+CREATE INDEX idx_source_labels_assigned_by ON source_labels(assigned_by);