Add generic configuration extension mechanism

[diyor28]

Problem

Projects using IOTA SDK need to register custom configuration sections that load from environment variables. Currently each project implements its own config loading logic, leading to:

• Duplicated helper functions (getEnvOrDefault, getEnvIntOrDefault)
• Inconsistent configuration patterns across projects
• No unified way to extend the SDK's configuration system

Use Case

shy-eld's Shyona module has agent configuration that needs to be loaded from environment variables. Currently this is duplicated between:

• modules/shyona/config.go - module config
• cmd/shyona-test/config.go - CLI config

Proposed Solution

Add a generic config extension mechanism using Go generics:

// ConfigExtension defines a configuration section that can be registered
type ConfigExtension interface {
    Prefix() string // e.g., "OPENAI_", "AGENTS_"
    Validate() error
}

// RegisterConfigExtension registers and loads a custom config section
func RegisterConfigExtension[T ConfigExtension](cfg *Configuration) (*T, error)

// Example usage:
type OpenAIConfig struct {
    APIKey    string
    Model     string
    MaxTokens int
}

func (c OpenAIConfig) Prefix() string { return "OPENAI_" }
func (c OpenAIConfig) Validate() error { /* ... */ }

// In application setup:
openaiCfg, err := configuration.RegisterConfigExtension[OpenAIConfig](cfg)

Acceptance Criteria

• Generic RegisterConfigExtension function that loads env vars based on prefix
• Support for common types (string, int, bool, duration)
• Validation hook for custom validation logic
• Documentation with usage examples
• No breaking changes to existing configuration

Related

• shy-eld#505

[claude]

Claude encountered an error —— View job

---

I'll analyze this and get back to you.