fix(campaigns): complete ACTION_LABELS map and timeline cache invalidation

Adds the 4 backend-logged campaign actions missing from ACTION_LABELS
(delete_campaign, generate_campaign, schedule_campaign,
recurring_campaign_run), and wires campaign-timeline invalidation into
the remaining audit-logging mutations on the page (complete, schedule,
approve/reject modification request) so the timeline panel updates
live instead of only on next reload, consistent with submit/approve/
reject campaign.

frontend/src/components/CampaignAuditTimeline.tsx

@@ -17,6 +17,10 @@ const ACTION_LABELS: Record<string, string> = {
   request_campaign_modification: "Modification requested",
   approve_campaign_modification: "Modification approved",
   reject_campaign_modification: "Modification rejected",
+  delete_campaign: "Campaign deleted",
+  generate_campaign: "Generated from threat actor",
+  schedule_campaign: "Schedule updated",
+  recurring_campaign_run: "Recurring run executed",
 };
 
 export default function CampaignAuditTimeline({ entries, isLoading }: Props) {