Aggregate lint, typecheck, builds, unit, Postgres journeys, and Web E2E
into a single Product CI check for branch protection. Soft-fail artifact
uploads and skip headless macOS screenshots so infra noise does not block
merge. Add autopilot/auto-merge workflow and MERGE_GATES.md.
Co-authored-by: cynarAI <cynarAI@users.noreply.github.com>