🐛 fix: add missing database environment variable bindings

- Add BindEnv calls for database configuration
- DLC_DATABASE_HOST, DLC_DATABASE_PORT, DLC_DATABASE_USER
- DLC_DATABASE_PASSWORD, DLC_DATABASE_NAME, DLC_DATABASE_SSL_MODE
- Enable environment variable override for database config
- Fix BDD test database connection issues

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

pkg/config/config.go

@@ -188,6 +188,14 @@ func LoadConfig() (*Config, error) {
 	// API environment variables
 	v.BindEnv("api.v2_enabled", "DLC_API_V2_ENABLED")
 
+	// Database environment variables
+	v.BindEnv("database.host", "DLC_DATABASE_HOST")
+	v.BindEnv("database.port", "DLC_DATABASE_PORT")
+	v.BindEnv("database.user", "DLC_DATABASE_USER")
+	v.BindEnv("database.password", "DLC_DATABASE_PASSWORD")
+	v.BindEnv("database.name", "DLC_DATABASE_NAME")
+	v.BindEnv("database.sslmode", "DLC_DATABASE_SSL_MODE")
+
 	// Unmarshal into Config struct
 	var config Config
 	if err := v.Unmarshal(&config); err != nil {