feat: Add threaded review comments + agent comment responses

Introduces GitHub-style threaded comments via parentCommentId self-reference.
Users and agents can reply within comment threads, and review agents receive
comment IDs so they can post targeted responses via comment-responses.json.

- Migration 0032: parentCommentId column + index on review_comments
- Repository: createReply() copies parent context, default author 'you' → 'user'
- tRPC: replyToReviewComment procedure, requestPhaseChanges passes threaded comments
- Orchestrator: formats [comment:ID] tags with full reply threads in task description
- Agent IO: readCommentResponses() reads .cw/output/comment-responses.json
- OutputHandler: processes agent comment responses (creates replies, resolves threads)
- Execute prompt: conditional <review_comments> block when task has [comment:] markers
- Frontend: CommentThread renders root+replies with agent-specific styling + reply form
- Sidebar/ReviewTab: root-only comment counts, reply mutation plumbing through DiffViewer chain

apps/server/agent/manager.ts

@@ -27,6 +27,7 @@ import type { TaskRepository } from '../db/repositories/task-repository.js';
 import type { PageRepository } from '../db/repositories/page-repository.js';
 import type { LogChunkRepository } from '../db/repositories/log-chunk-repository.js';
 import type { ChatSessionRepository } from '../db/repositories/chat-session-repository.js';
+import type { ReviewCommentRepository } from '../db/repositories/review-comment-repository.js';
 import { generateUniqueAlias } from './alias.js';
 import type {
   EventBus,
@@ -84,11 +85,12 @@ export class MultiProviderAgentManager implements AgentManager {
     private debug: boolean = false,
     processManagerOverride?: ProcessManager,
     private chatSessionRepository?: ChatSessionRepository,
+    private reviewCommentRepository?: ReviewCommentRepository,
   ) {
     this.signalManager = new FileSystemSignalManager();
     this.processManager = processManagerOverride ?? new ProcessManager(workspaceRoot, projectRepository);
     this.credentialHandler = new CredentialHandler(workspaceRoot, accountRepository, credentialManager);
-    this.outputHandler = new OutputHandler(repository, eventBus, changeSetRepository, phaseRepository, taskRepository, pageRepository, this.signalManager, chatSessionRepository);
+    this.outputHandler = new OutputHandler(repository, eventBus, changeSetRepository, phaseRepository, taskRepository, pageRepository, this.signalManager, chatSessionRepository, reviewCommentRepository);
     this.cleanupManager = new CleanupManager(workspaceRoot, repository, projectRepository, eventBus, debug, this.signalManager);
     this.lifecycleController = createLifecycleController({
       repository,