Track cookie policy generation requests on publish

Add policy_document_id and policy_generation_requested_at columns to
cookie_banners and backfill banners that already have a published
version, so existing live banners get a policy on the worker's first
pass.

Flag the banner for policy generation inside the publish transaction so
generation is requested only when a cookie banner version is published,
not on draft edits. Fold policy_document_id into the existing Update so
the upcoming worker can persist the generated document id with the
scope it already holds.

Signed-off-by: Émile Ré <emile@probo.com>

pkg/cookiebanner/service.go

@@ -964,6 +964,11 @@ func (s *Service) PublishCookieBannerVersion(
 				return fmt.Errorf("cannot publish version: %w", err)
 			}
 
+			banner := coredata.CookieBanner{ID: bannerID}
+			if err := banner.SetPolicyGenerationRequested(ctx, tx); err != nil {
+				return fmt.Errorf("cannot request cookie policy generation: %w", err)
+			}
+
 			return nil
 		},
 	)