Add documentation for session creation and decorator usage

[devin-ai-integration]

Description

Currently, there is no clear documentation on how to create sessions and use the decorators for the AgentOps SDK. This makes it difficult for users to understand how to properly implement these features.

Requirements

• Add documentation on how to create and manage sessions
• Add documentation on how to use the various decorators (@agent, @task, @operation, @workflow, @session)
• Include code examples for both synchronous and asynchronous usage
• Update the SDK reference documentation

Acceptance Criteria

• Documentation is clear and comprehensive
• Code examples are provided for all use cases
• Documentation is accessible in the docs/v1/usage/ directory

[SupremeIA]

Cool