Phase 3 — Python coverage for atomr-accel-telemetry

[cognect]

Wrap atomr-accel-telemetry for Python so users can drive observability primitives from notebooks / scripts.

Scope

atomr-accel-telemetry

Wrap as python/atomr_accel/telemetry.py + src/telemetry.rs (gated on
the upstream telemetry cargo feature):

• NvtxKernelTrace — NVTX kernel-range markers.
• NvmlActor — power/temp/ECC/clock probes.
• CuptiSession — CUPTI activity tracing.

Hooks

The CUDA crate's observability module installs an atomr-telemetry
extension on the actor system. Phase 3 should:

1. Surface TelemetryBus.subscribe_topic(...) from upstream's
   atomr-pycore (already wrapped there as atomr.telemetry.TelemetryBus).
2. Add Device.enable_telemetry() to install the extension at runtime.
3. Wrap NvtxKernelTrace::span(name) as a Python context manager
   that emits a CUDA NVTX range around its body.

Non-goals

• atomr-accel-cuda-realtime (covered in Phase 2 — Python coverage for patterns / train / agents / cuda-realtime #2).
• Full method-level depth for cuDNN/cuFFT/etc. (issue Phase 1.5 — atomr-accel-cuda Python method-level depth #1).