fix: Add missing event routing for initiative status real-time refresh

7 of 12 initiative activity state transitions were broken due to missing
event routing at three layers: SSE event arrays, live-update prefix rules,
and mutation invalidation map.

- Add initiative:changes_requested to ALL_EVENT_TYPES and TASK_EVENT_TYPES
- Add initiative:/agent: prefix rules to initiatives list and detail pages
- Add approveInitiativeReview, requestInitiativeChanges, requestPhaseChanges
  to INVALIDATION_MAP; add listInitiatives to approvePhase
- Extract INITIATIVE_LIST_RULES constant for reuse

apps/server/trpc/subscriptions.ts

@@ -70,6 +70,7 @@ export const ALL_EVENT_TYPES: DomainEventType[] = [
   'chat:session_closed',
   'initiative:pending_review',
   'initiative:review_approved',
+  'initiative:changes_requested',
 ];
 
 /**
@@ -102,6 +103,7 @@ export const TASK_EVENT_TYPES: DomainEventType[] = [
   'phase:merged',
   'initiative:pending_review',
   'initiative:review_approved',
+  'initiative:changes_requested',
 ];
 
 /**