Make the dashboard a grid of projects with their inbox

DashboardView drops the placeholder for a full-width grid of project cards.
Each card links to the project and lists its inbox cards (status_id === null)
under a "New" heading, or "Nothing new." when empty. Cards are fetched per
project (one GET /projects/{id}/cards each) after the project list resolves.

projects store: fetchProjects() now shares one in-flight request between
concurrent callers (the sidebar and the dashboard mount together).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/router/index.ts

@@ -9,7 +9,7 @@ const router = createRouter({
       path: '/dashboard',
       name: 'dashboard',
       component: () => import('../views/DashboardView.vue'),
-      meta: { requiresAuth: true },
+      meta: { requiresAuth: true, wide: true },
     },
     {
       path: '/projects/:id(\\d+)',