Record successful Colab smoke validation

[Kauandugi]

What changed

• allows WSL path conversion for output files that do not exist yet
• avoids invoking drive.mount() again when the CLI session has already mounted Google Drive
• marks the real four-image T4 smoke test as completed in OpenSpec
• adds regression assertions for the mounted-Drive notebook path

Live validation

The official notebook was executed through the Colab CLI on a Tesla T4 using commit f1bf3fe.

• 64 input images discovered during preflight
• deterministic tests passed in the Colab runtime
• 4 smoke images processed
• 35 faces written under the 1:N contract
• CLIP diversity scores written only at image level
• Mann-Whitney and Wilcoxon reports generated at image level
• final output validator returned exit code 0
• local executed notebook and JSONL/IPYNB session logs exported
• Colab session stopped and server reported no active sessions

Local regression suite after the wrapper/notebook fixes: 29 passed, 1 skipped, coverage 89.43%.