Add callbacks for driver cuGraphLaunch

[gnurizen]

Problem

parcagpu subscribed to CUPTI callbacks for eager kernel launches (cuLaunchKernel) and runtime graph launches (cudaGraphLaunch), but not the driver-API graph launch (cuGraphLaunch / cuGraphLaunch_ptsz). setLaunchCallbacks covers only kernel-launch cbids and setRuntimeCallbacks only the runtime domain, so the driver graph-launch cbid was never enabled.

C++ runtimes such as TensorRT-LLM replay CUDA graphs through the driver API. On those workloads the cuda_correlation USDT never fired for graph launches, no CUDA_KERNEL frame was pushed, and the GPU sample pipeline produced nothing in graph mode — while eager launches kept working. This was confirmed on a 4×B200 TRT-LLM node: a trace_pipe capture in graph mode contained zero FRAME_MARKER_CUDA_KERNEL frames.

Fix

Enable only the two driver graph-launch cbids in CuptiProfiler::initialize (with symmetric teardown). Deliberately not setGraphCallbacks(), which also subscribes the capture (cuStreamBegin/EndCapture) and graph-resource cbids — those would make callbackHandler emit correlation events for non-executing capture calls that never receive kernel timing. The existing isGraphLaunch handler already had all the logic to process these callbacks; it just never received them.

Test coverage

The mock harness previously dispatched the shim's callback unconditionally, so a missing subscription was invisible to tests. Changes:

• mock_cupti.c: cuptiEnableCallback now records the subscribed (domain, cbid) set.
• test_cupti_prof.c: callbacks are dispatched only if subscribed, mirroring real CUPTI gating.
• test-pc-mock-graph.sh: asserts driver cuGraphLaunch correlation events fire (signed cbid -514/-515). The workload splits graph launches 50/50 runtime/driver, so the runtime half emits regardless — only this check catches the regression. Wired to a new make test-pc-mock-graph target.
• graph_repro.cu / graph-repro-real.sh: real-GPU reproducer that replays a captured graph via driver cuGraphLaunch and verifies correlation events fire.

Verified the mock guard goes red without the fix and green with it.