[CURATOR-598] InterProcessSemaphoreV2::getData to check against data changes on the semaphore

InterProcessSemaphoreV2 allows holders to set data on the acquired lease: exposing an Optional getData would allow an observer to check against mutex state change despite not being the lock owner (assuming owner has used setData prior a mutex acquisition).

This can be used to weakly enforce order of mutex acquisition or just check owner's identity and/or presence (assuming owner setData prior a mutex acquisition).

---
Originally reported by nigrofranz, imported from: InterProcessSemaphoreV2::getData to check against data changes on the semaphore

• status: Open
  
• priority: Major
  
• resolution: Unresolved
  
• imported: 2025-01-21
  

Start at the InterProcessSemaphoreV2 entry point and trace how data is set on an acquired lease. Define the expected Optional getData behavior for observers, including owner-set data and absent data, then add coverage in the semaphore tests and verify observers can detect the relevant state changes.

Written by the indexing model from the issue text.