fix(manacore): fix white screen when toggling todo completion in dashboard

Task links pointed to non-existent /task/{id} route in Todo app, causing
navigation to a 404 page. Replace passive checkbox div with interactive
button that toggles completion via API, and fix links to open Todo app root.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/manacore/apps/web/src/lib/api/services/todo.ts

@@ -160,6 +160,32 @@ export const todoService = {
 		return { data: result.data.projects || [], error: null };
 	},
 
+	/**
+	 * Mark a task as complete
+	 */
+	async completeTask(id: string): Promise<ApiResult<Task>> {
+		const result = await getClient().post<{ task: Task }>(`/tasks/${id}/complete`);
+
+		if (result.error || !result.data) {
+			return { data: null, error: result.error };
+		}
+
+		return { data: result.data.task, error: null };
+	},
+
+	/**
+	 * Mark a task as incomplete
+	 */
+	async uncompleteTask(id: string): Promise<ApiResult<Task>> {
+		const result = await getClient().post<{ task: Task }>(`/tasks/${id}/uncomplete`);
+
+		if (result.error || !result.data) {
+			return { data: null, error: result.error };
+		}
+
+		return { data: result.data.task, error: null };
+	},
+
 	/**
 	 * Get task count summary
 	 */

apps/manacore/apps/web/src/lib/components/dashboard/widgets/TasksTodayWidget.svelte

@@ -78,7 +78,7 @@
 	const totalCount = $derived((data || []).length);
 
 	// Track tasks being toggled (for optimistic UI)
-	let togglingIds = $state<Set<string>>(new Set());
+	let togglingIds: Set<string> = $state(new Set());
 
 	async function handleToggleComplete(e: MouseEvent, task: Task) {
 		e.preventDefault();

apps/manacore/apps/web/src/lib/components/dashboard/widgets/TasksUpcomingWidget.svelte

@@ -108,7 +108,9 @@
 		<div class="space-y-1">
 			{#each displayedTasks as task}
 				<a
-					href="{todoUrl}/task/{task.id}"
+					href={todoUrl}
+					target="_blank"
+					rel="noopener"
 					class="flex items-center gap-2.5 rounded-lg px-2 py-1.5 transition-colors hover:bg-surface-hover"
 				>
 					<!-- Priority dot -->