Expose a non-destructive re-trigger that re-arms tracker policy
generation for a banner that already has a published version, so the
tracker-policy worker regenerates the document after iterating on the
generator. RegenerateTrackerPolicy returns a conflict when nothing has
been published yet.
Wire it across all API surfaces per the api-surface rule: the console
GraphQL mutation and resolver, the MCP tool, the prb cookie-banner
regenerate-policy command, and the n8n operation, with console e2e
coverage for the success and no-published-version paths.
Signed-off-by: Émile Ré <emile@probo.com>