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+# Phase 4 Implementation Progress
+
+**Status:** 22/68 tasks completed (32.4%)
+
+**Test Coverage:** 170 unit tests, all passing ✅
+
+---
+
+## Completed Modules
+
+### 1. Authentication Infrastructure
+- ✅ JWT Service (access token + refresh token)
+- ✅ Password Hasher (bcrypt, cost=12)
+- ✅ Session Store (Redis-based)
+- ✅ Email Service (SMTP with templates)
+
+### 2. User Authentication Flow
+- ✅ User Registration (with email verification)
+- ✅ Email Verification
+- ✅ User Login (JWT + Session)
+- ✅ User Logout (single device / all devices)
+- ✅ Password Reset (email-based)
+
+### 3. Workspace Management
+- ✅ Create Workspace
+- ✅ Invite Members (with email invitation)
+- ✅ Accept / Decline Invitation
+- ✅ Remove Members
+- ✅ Leave Workspace
+- ✅ Update Member Role
+- ✅ List Workspaces (user's all workspaces)
+- ✅ Get Workspace Detail
+- ✅ List Members
+
+### 4. Permission System
+- ✅ Permission Checker (role-based access control)
+- ✅ Role Permissions Mapping (Owner/Admin/Member/Viewer)
+- ✅ Permission Constants (workspace/member/project/asset)
+
+### 5. Subscription Management
+- ✅ Upgrade Subscription (Free→Pro→Enterprise)
+- ✅ Cancel Subscription (downgrade to Free)
+- ✅ Auto-configure quotas based on plan
+
+### 6. Quota System
+- ✅ Quota Checker (project count + storage usage)
+- ✅ Quota Status (usage percentage)
+- ✅ Warning Levels (normal/warning/critical/exceeded)
+- ✅ Update Storage Usage
+
+### 7. Repository Layer
+- ✅ UserRepository (interface + InMemory)
+- ✅ WorkspaceRepository (interface + InMemory)
+- ✅ WorkspaceMemberRepository (interface + InMemory)
+- ✅ WorkspaceInvitationRepository (interface + InMemory)
+- ✅ ProjectRepository (interface only, for quota check)
+
+---
+
+## Remaining Tasks (46/68)
+
+### High Priority
+- [ ] API Routes Integration (FastAPI)
+- [ ] Database Migration Scripts (PostgreSQL)
+- [ ] PostgreSQL Repository Implementation
+- [ ] API Documentation (Swagger)
+
+### Medium Priority
+- [ ] Frontend Integration Preparation
+- [ ] Error Handling & Validation Middleware
+- [ ] Rate Limiting
+- [ ] Logging & Monitoring
+
+### Low Priority
+- [ ] Payment Integration (Stripe/Alipay)
+- [ ] Webhook Handlers
+- [ ] Admin Dashboard
+- [ ] Analytics & Metrics
+
+---
+
+## Next Steps
+
+1. **API Routes** - Implement FastAPI routes for all use cases
+2. **Database** - PostgreSQL repositories and migration scripts
+3. **Testing** - Integration tests for API endpoints
+4. **Deployment** - Update deployment configuration
+5. **Documentation** - API documentation and user guides
+
+---
+
+**Last Updated:** 2026-06-17 07:27 GMT+8