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/dispatch/manager.ts

@@ -359,8 +359,8 @@ export class DefaultDispatchManager implements DispatchManager {
 
             const phase = await this.phaseRepository.findById(task.phaseId);
             if (phase) {
-              if (task.category === 'merge') {
-                // Merge tasks work directly on the phase branch
+              if (task.category === 'merge' || task.category === 'review') {
+                // Merge/review tasks work directly on the phase branch
                 baseBranch = initBranch;
                 branchName = phaseBranchName(initBranch, phase.name);
               } else {