Reapply "Merge: t-paliad-133 — Fristenrechner v3 (Pathway A/B fork + B1 decision tree + B2 forum filter + retire legacy tabs)"

This reverts commit 5bd17de732.

cmd/server/main.go

@@ -143,6 +143,7 @@ func main() {
 			Fristenrechner: services.NewFristenrechnerService(rules, holidays),
 			EventDeadline:  services.NewEventDeadlineService(pool, services.NewDeadlineCalculator(holidays), holidays),
 			DeadlineSearch: services.NewDeadlineSearchService(pool),
+			EventCategory:  nil, // wired below; cross-link order matters
 			EventType:      eventTypeSvc,
 			Dashboard:      services.NewDashboardService(pool, users),
 			Note:           services.NewNoteService(pool, projectSvc, appointmentSvc),
@@ -155,6 +156,12 @@ func main() {
 			Link:           services.NewLinkService(pool),
 			Event:          services.NewEventService(pool, deadlineSvc, appointmentSvc),
 		}
+		// v3 (t-paliad-133): wire EventCategoryService and cross-link
+		// it into DeadlineSearchService so ?event_category_slug= can
+		// resolve to a concept-id allow-list during search.
+		eventCategorySvc := services.NewEventCategoryService(pool)
+		svcBundle.EventCategory = eventCategorySvc
+		svcBundle.DeadlineSearch.SetEventCategoryService(eventCategorySvc)
 		log.Println("Phase B services initialised")
 
 		// Spawn background goroutines: CalDAV sync (one per enabled user)