chore(phase0): reproducible compute gate — torch cu130 + GPU smoke test

scripts/check_gpu.py verifies PyTorch cu130 sees the koala Blackwell GPU
(sm_120) and computes — the Phase-0 prerequisite before any autoresearch
experiment. Verified green: torch 2.12.1+cu130, RTX 5070, GPU matmul OK.
Note: koala GPU is shared with the llama-swap LLM stack — run the autoresearch
agent on iguana/berget so the card stays free for train.py.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -28,3 +28,6 @@ go.work.sum
 # Project-specific
 bin/
 *.templ.go
+
+# python venv (autoresearch loop)
+.venv/