Add comprehensive usage examples for token managers

[leogdion]

Description

Create detailed usage examples and documentation for all TokenManager implementations to help developers understand and implement token management strategies.

Background

CodeRabbit review of PR #105 identified missing documentation for TokenManager usage patterns. Current 40 undocumented public declarations include key TokenManager methods.

Required Examples

1. InMemoryTokenStorage

• Basic setup and configuration
• Token storage and retrieval
• Memory management considerations
• Use case scenarios

2. Custom TokenManager Implementation

• Protocol conformance examples
• Persistent storage implementations
• Thread safety considerations
• Error handling patterns

3. Integration Examples

• TokenManager with MistKitConfiguration
• Token refresh workflows
• Multiple environment management
• Testing with mock TokenManagers

Documentation Tasks

• Add @throws and @returns documentation for all TokenManager methods
• Document TokenManagerError types and handling
• Create comprehensive code examples
• Add performance and security considerations
• Document testing strategies for token management

Code Examples Needed

// InMemoryTokenStorage usage
let tokenStorage = InMemoryTokenStorage()
let config = MistKitConfiguration(tokenManager: tokenStorage, ...)

// Custom TokenManager implementation
class CustomTokenManager: TokenManager {
    // Implementation example
}

// Error handling patterns
do {
    let token = try await tokenManager.getToken()
} catch let error as TokenManagerError {
    // Handle specific token errors
}

Acceptance Criteria

• All TokenManager implementations have usage examples
• Error handling patterns are documented
• Performance and security guidelines exist
• Examples cover common use cases and edge cases

Related

• PR Adding Server to Server Authentication #105 feedback
• API documentation improvements
• Authentication system documentation

Labels

documentation, token-management, examples, api

[leogdion]

Need to verify TokenManager usage examples exist in documentation.