[Bug]: Inconsistency for task.id vs contextId or messageId

### What happened?

In task object, the id is called `id` , that is inconsistent with other object like Message or Context or Artifact where the id is called messageId or contextId or artifactId. I suggest we have a more consistent naming for id field across all objects. I would prefer changing task.id to task.taskId .

### Relevant log output

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### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

Find the Task object definition in the codebase, likely in a models or schemas directory. Compare with definitions for Message, Context, and Artifact to understand the current naming. Change the field from 'id' to 'taskId' in the Task class/struct and update all references. Run existing tests to ensure no regressions.

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