Promote golden-path demo as ongoing trust-building ritual

[ProtocolWarden]

Context

The golden-path demo (docs/demo.md or equivalent) shows the full autonomy cycle: observe → insights → decide → propose → task created in Plane. This demo should be kept runnable and used as a validation ritual after significant changes to the autonomy loop.

Goal

Update the README and demo docs to position the golden-path demo not just as a getting-started guide but as an ongoing trust ritual — something to run after threshold tuning, after new family promotion, or after worker restarts.

Acceptance Criteria

• README links to demo and describes it as a validation ritual
• Demo script is self-contained and runnable in under 5 minutes
• Demo output includes artifact paths so the run is auditable
• Demo is listed in the operator runbook as a post-change validation step

Labels

demo, operator-docs, trust