# Progress Tracker: Sync Control Panel & DLQ UI

## Task Context
Implementation of a full-stack remediation layer for multi-tenant sync architecture, including field mapping and a Dead Letter Queue (DLQ) dashboard.

## Objectives
- [x] Backend: Infrastructure tables (`field_metadata`, `dead_letter_events`) on `mysql` connection.
- [x] Backend: REST API controllers (`SyncMetadataController`, `SyncDlqController`).
- [x] Frontend: React components (`SyncFieldMapper`, `DlqDashboard`, `DlqInspectorModal`).
- [x] Integration: API routes with regex validation and tenant isolation.
- [x] Quality: Optimistic Locking guard on `SyncMetadataController::store()`. PHPStan ✅ 0 errors.

| Phase | Status | Details |
|-------|--------|---------|
| Phase 0: Initialization | ✅ | Branch `feature/sync-control-panel` created, tracker initialized. |
| Phase 0.5: Context Scan | ✅ | Standards, security rules, and performance rules reviewed. |
| Phase 1: Requirements & Schema | ✅ | Migrations and models validated. |
| Phase 2: Architectural Design | ✅ | DDD placement confirmed. Controllers extend BaseApiController. |
| Phase 3: Implementation Plan | ✅ | Controllers, components, and routes implemented. |
| Phase 4: Verification Plan | ✅ | PHPStan level 5: 0 errors. Bug inspection complete. |
| Phase 5: Handoff | ✅ | Optimistic Locking guard added. Bug Analysis Report delivered. |

## Fix Log
| ID | Fix | Bug Title | Status | Description |
|----|-----|-----------|--------|-------------|
| 01 | Optimistic Locking | Concurrent Metadata Overwrite | ✅ Done | Added `client_version` check in `store()`. Returns HTTP 409 on conflict. |
| 02 | DLQ Operations | Silent failure on Retry/Dismiss | ✅ Done | Implemented mock-aware logic and user feedback (banners). |
| 03 | State Reset | False 409 Conflicts Post-Save | ✅ Done | Ensured absolute state reset using `{ ...INITIAL_FORM }`. |