feat : add task management with kanban and backlog

Add kanban board with drag-and-drop, backlog section, task/group
drawers, DTOs, services, and i18n translations.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/services/projects.ts

@@ -10,6 +10,10 @@ export function useProjectService() {
         return extractHydraMembers(data)
     }
 
+    async function getById(id: number): Promise<Project> {
+        return api.get<Project>(`/projects/${id}`)
+    }
+
     async function create(payload: ProjectWrite): Promise<Project> {
         return api.post<Project>('/projects', payload as Record<string, unknown>, {
             toastSuccessKey: 'projects.created',
@@ -28,5 +32,5 @@ export function useProjectService() {
         })
     }
 
-    return { getAll, create, update, remove }
+    return { getAll, getById, create, update, remove }
 }