Add support for Claude

[GSSwain]

Add support for Claude as the cloud agent which meets the below requirements.

• Claude needs to be configured following the same pattern as Gemini i.e. through an api key
• The agent avialability check is extended to support Claude which verifies a key is configured and Claude is reachable.

For task execution:

• If only Claude is online, then it handles Medium, Complex and Very Complex tasks.
• If Gemini and Claude both are online, then Gemini handles tasks with Medium complexity while Claude handles Complex and Very Complex tasks.
• If only Gemini is available then it handles Medium, Complex and Very Complex tasks.
• Local Gemma model handles simple tasks as well as classifying the task.
• The task router needs to be aware of the agent availability to route the tasks.

Update documentation on how to setup Claude.

[GSSwain]

This feature is implemented part of PR #8