fix: update search_path from kanzlai to mgmt after migration

backend/internal/db/connection.go

@@ -13,8 +13,8 @@ func Connect(databaseURL string) (*sqlx.DB, error) {
 		return nil, fmt.Errorf("connecting to database: %w", err)
 	}
 
-	// Set search_path so queries use kanzlai schema by default
-	if _, err := db.Exec("SET search_path TO kanzlai, public"); err != nil {
+	// Set search_path so queries use mgmt schema by default
+	if _, err := db.Exec("SET search_path TO mgmt, public"); err != nil {
 		db.Close()
 		return nil, fmt.Errorf("setting search_path: %w", err)
 	}