feat: Wire full request-changes flow for phase review

- Add PhaseChangesRequestedEvent to event bus
- Add requestChangesOnPhase() to ExecutionOrchestrator: reads unresolved
  comments, creates revision task (category='review'), resets phase to
  in_progress, queues task for dispatch
- Expand merge-skip and branch routing to include 'review' category so
  revision tasks work directly on the phase branch
- Add requestPhaseChanges tRPC procedure (reads comments from DB)
- Wire frontend: mutation replaces stub handler, window.prompt for
  optional summary, loading state on button

apps/server/events/index.ts

@@ -38,6 +38,7 @@ export type {
   PhaseCompletedEvent,
   PhaseBlockedEvent,
   PhasePendingReviewEvent,
+  PhaseChangesRequestedEvent,
   PhaseMergedEvent,
   TaskMergedEvent,
   MergeQueuedEvent,

apps/server/events/types.ts

@@ -329,6 +329,16 @@ export interface PhasePendingReviewEvent extends DomainEvent {
   };
 }
 
+export interface PhaseChangesRequestedEvent extends DomainEvent {
+  type: 'phase:changes_requested';
+  payload: {
+    phaseId: string;
+    initiativeId: string;
+    taskId: string;
+    commentCount: number;
+  };
+}
+
 export interface PhaseMergedEvent extends DomainEvent {
   type: 'phase:merged';
   payload: {
@@ -595,6 +605,7 @@ export type DomainEventMap =
   | PhaseCompletedEvent
   | PhaseBlockedEvent
   | PhasePendingReviewEvent
+  | PhaseChangesRequestedEvent
   | PhaseMergedEvent
   | TaskMergedEvent
   | MergeQueuedEvent