Fail fast when a release tag already exists instead of running the
full build+package cycle only to fail at git push. Saves CI time on
duplicate workflow_dispatch triggers.
Adds a security audit step (npm audit --omit=dev) to catch known
vulnerabilities in production dependencies. Runs after tests so build
failures are reported before audit findings. Uses --omit=dev to focus
on production-facing risk.
This covers all 6 plugin repos that use the shared workflow.