- Add ApiKeySource type ('inline' | 'env' | 'credentials') to ClaudeApiProfile
- Allow profiles to source API keys from credentials.json or environment variables
- Add provider templates: OpenRouter, MiniMax, MiniMax (China)
- Auto-migrate existing users with Anthropic key to "Direct Anthropic" profile
- Update all API call sites to pass credentials for key resolution
- Add API key source selector to profile creation UI
- Increment settings version to 5 for migration support
This allows users to:
- Share a single API key across multiple profile configurations
- Use environment variables for CI/CD deployments
- Easily switch between providers without re-entering keys
