feat(backend): Implement complete Project Management Module with multi-tenant support

Day 12 implementation - Complete CRUD operations with tenant isolation and SignalR integration.

**Domain Layer**:
- Added TenantId value object for strong typing
- Updated Project entity to include TenantId field
- Modified Project.Create factory method to require tenantId parameter
- Updated ProjectCreatedEvent to include TenantId

**Application Layer**:
- Created UpdateProjectCommand, Handler, and Validator for project updates
- Created ArchiveProjectCommand, Handler, and Validator for archiving projects
- Updated CreateProjectCommand to include TenantId
- Modified CreateProjectCommandValidator to remove OwnerId validation (set from JWT)
- Created IProjectNotificationService interface for SignalR abstraction
- Implemented ProjectCreatedEventHandler with SignalR notifications
- Implemented ProjectUpdatedEventHandler with SignalR notifications
- Implemented ProjectArchivedEventHandler with SignalR notifications

**Infrastructure Layer**:
- Updated PMDbContext to inject IHttpContextAccessor
- Configured Global Query Filter for automatic tenant isolation
- Added TenantId property mapping in ProjectConfiguration
- Created TenantId index for query performance

**API Layer**:
- Updated ProjectsController with [Authorize] attribute
- Implemented PUT /api/v1/projects/{id} for updates
- Implemented DELETE /api/v1/projects/{id} for archiving
- Added helper methods to extract TenantId and UserId from JWT claims
- Extended IRealtimeNotificationService with Project-specific methods
- Implemented RealtimeNotificationService with tenant-aware SignalR groups
- Created ProjectNotificationServiceAdapter to bridge layers
- Registered IProjectNotificationService in Program.cs

**Features Implemented**:
- Complete CRUD operations (Create, Read, Update, Archive)
- Multi-tenant isolation via EF Core Global Query Filter
- JWT-based authorization on all endpoints
- SignalR real-time notifications for all Project events
- Clean Architecture with proper layer separation
- Domain Event pattern with MediatR

**Database Migration**:
- Migration created (not applied yet): AddTenantIdToProject

**Test Scripts**:
- Created comprehensive test scripts (test-project-simple.ps1)
- Tests cover full CRUD lifecycle and tenant isolation

**Note**: API hot reload required to apply CreateProjectCommandValidator fix.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

colaflow-api/src/ColaFlow.API/Services/RealtimeNotificationService.cs

@@ -19,6 +19,37 @@ public class RealtimeNotificationService : IRealtimeNotificationService
         _logger = logger;
     }
 
+    public async Task NotifyProjectCreated(Guid tenantId, Guid projectId, object project)
+    {
+        var tenantGroupName = $"tenant-{tenantId}";
+
+        _logger.LogInformation("Notifying tenant {TenantId} of new project {ProjectId}", tenantId, projectId);
+
+        await _projectHubContext.Clients.Group(tenantGroupName).SendAsync("ProjectCreated", project);
+    }
+
+    public async Task NotifyProjectUpdated(Guid tenantId, Guid projectId, object project)
+    {
+        var projectGroupName = $"project-{projectId}";
+        var tenantGroupName = $"tenant-{tenantId}";
+
+        _logger.LogInformation("Notifying project {ProjectId} updated", projectId);
+
+        await _projectHubContext.Clients.Group(projectGroupName).SendAsync("ProjectUpdated", project);
+        await _projectHubContext.Clients.Group(tenantGroupName).SendAsync("ProjectUpdated", project);
+    }
+
+    public async Task NotifyProjectArchived(Guid tenantId, Guid projectId)
+    {
+        var projectGroupName = $"project-{projectId}";
+        var tenantGroupName = $"tenant-{tenantId}";
+
+        _logger.LogInformation("Notifying project {ProjectId} archived", projectId);
+
+        await _projectHubContext.Clients.Group(projectGroupName).SendAsync("ProjectArchived", new { ProjectId = projectId });
+        await _projectHubContext.Clients.Group(tenantGroupName).SendAsync("ProjectArchived", new { ProjectId = projectId });
+    }
+
     public async Task NotifyProjectUpdate(Guid tenantId, Guid projectId, object data)
     {
         var groupName = $"project-{projectId}";