docs: Document MonitorService IllegalStateException as Demo Feature-created-by-agentic

[shaykeren]

Documentation Update for MonitorService Exception

This PR adds documentation to clarify that the IllegalStateException thrown in MonitorService.monitor() is an intentional demonstration feature.

Changes Made:

• Added JavaDoc comments to the monitor() method explaining the intentional exception
• Created documentation in code to prevent future confusion
• Related to issue Documentation: MonitorService IllegalStateException is an Intentional Demo Feature-created-by-agentic #207

Purpose:

This documentation update helps prevent false alarms and clarifies that the exception is a demonstration feature for error handling capabilities.

Testing:

No functional changes were made, only documentation updates.