[GPU][debug] Network marker (#35196)
### Details:
- Adds a debug option (GPU_NETWORK_MARKER) that inserts named no-op
OpenCL marker kernels at network execution start/finish boundaries. This
allows tools like CLIntercept to identify network execution regions in
call logs.
- Marker kernels are named
[network_marker_{start|finish}_p{prog_id}_n{net_id}]
- Iteration number is encoded in GWS x-dimension (1-based) for easy
identification
- Kernels are compiled once and cached; enqueued on the network's own
command queue
- Zero overhead when disabled (default: off)
### AI Assistance:
- *AI assistance used: yes*
- AI was used to implement the feature.
