fix: Fix review task completion bug + add initiative-level Request Changes

Critical: review/merge tasks hit an early return in handleTaskCompleted()
that skipped the phase completion check, leaving phases stuck in
in_progress forever. Changed to an if-block wrapping only the merge step.

Also adds requestChangesOnInitiative() which creates/reuses a
"Finalization" phase for initiative-level review feedback, with dedup
guards for both phase and initiative request-changes flows.

apps/server/events/index.ts

@@ -52,6 +52,7 @@ export type {
   AccountCredentialsValidatedEvent,
   InitiativePendingReviewEvent,
   InitiativeReviewApprovedEvent,
+  InitiativeChangesRequestedEvent,
   DomainEventMap,
   DomainEventType,
 } from './types.js';

apps/server/events/types.ts

@@ -591,6 +591,15 @@ export interface InitiativeReviewApprovedEvent extends DomainEvent {
   };
 }
 
+export interface InitiativeChangesRequestedEvent extends DomainEvent {
+  type: 'initiative:changes_requested';
+  payload: {
+    initiativeId: string;
+    phaseId: string;
+    taskId: string;
+  };
+}
+
 /**
  * Chat Session Events
  */
@@ -668,7 +677,8 @@ export type DomainEventMap =
   | ChatMessageCreatedEvent
   | ChatSessionClosedEvent
   | InitiativePendingReviewEvent
-  | InitiativeReviewApprovedEvent;
+  | InitiativeReviewApprovedEvent
+  | InitiativeChangesRequestedEvent;
 
 /**
  * Event type literal union for type checking