refactor: use actors for db configuration (#1604)

Co-authored-by: Claude <noreply@anthropic.com>

backend/internal/appconfig/testing_unit.go

@@ -0,0 +1,27 @@
+//go:build unit
+
+// This file contains utils for unit tests and it's only built when the "unit" tag is set
+package appconfig
+
+// NewTestAppConfigService is a function used by tests to create AppConfigService objects with pre-defined configuration values
+func NewTestAppConfigService(config *AppConfigModel) *AppConfigService {
+	if config == nil {
+		// If there's no config, set the default one
+		config = getDefaultConfig()
+	}
+
+	service := &AppConfigService{
+		envConfig: config,
+	}
+
+	return service
+}
+
+// NewTestConfig returns an application configuration for use in tests, falling back to the default configuration when none is provided
+func NewTestConfig(config *AppConfigModel) *AppConfigModel {
+	if config == nil {
+		config = getDefaultConfig()
+	}
+
+	return config
+}