chore(training): EchidnaML CUDA logging fix + per-stage run doc (#232)

EchidnaML.jl: CUDA.version() was removed in CUDA.jl 5.x; replace with
runtime_version() / driver_version() wrapped in try/catch so a
logging-only probe failure can't kill the init path. Surfaced during
first owner-authorised GNN training run as a MethodError log noise.

docs/training-runs/2026-06-02.md: per-stage run-log scaffold for the
2026-06-02 GNN training run (reactive doc — placeholders for stages
3/4/5 to be filled in as they complete; stage 0/1/2 outcomes already
captured).

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath