refactor: improve handling of optional CustomerID in project models and DTOs

backend/internal/db/db.go

@@ -80,7 +80,7 @@ func MigrateDB() error {
 // createConnection creates a new database connection with the given configuration
 func createConnection(dbConfig config.DatabaseConfig, dbName string) (*gorm.DB, error) {
 	// Create DSN (Data Source Name)
-	dsn := fmt.Sprintf("host=%s port=%d user=%s password=%s dbName=%s sslmode=%s",
+	dsn := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
 		dbConfig.Host, dbConfig.Port, dbConfig.User, dbConfig.Password, dbName, dbConfig.SSLMode)
 
 	// Configure GORM logger