feat: study home with daily plan card and quick actions

test/study_plan_test.dart

@@ -0,0 +1,57 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mobile/models/study_plan.dart';
+
+void main() {
+  test('预计用时按条目数与平均耗时向上取整', () {
+    // 18 + 35 = 53 条 × 13 秒 = 689 秒 → 12 分钟
+    expect(StudyPlan.sample.itemCount, 53);
+    expect(StudyPlan.sample.estimatedMinutes, 12);
+    expect(StudyPlan.sample.estimatedLabel, '预计用时 12 分钟');
+  });
+
+  test('没有任务时不给时长承诺，也不算空转', () {
+    const StudyPlan plan = StudyPlan(
+      deckName: '空单元集',
+      algorithm: 'SM-2',
+      totalItems: 10,
+      activatedItems: 0,
+      dueItems: 0,
+      newItems: 0,
+      secondsPerItem: 13,
+    );
+
+    expect(plan.isEmpty, isTrue);
+    expect(plan.estimatedMinutes, 0);
+    expect(plan.estimatedLabel, '今天没有到期的内容');
+  });
+
+  test('完成度保留一位小数', () {
+    const StudyPlan plan = StudyPlan(
+      deckName: '高考必背古诗文',
+      algorithm: 'NSP-0',
+      totalItems: 950,
+      activatedItems: 295,
+      dueItems: 0,
+      newItems: 0,
+      secondsPerItem: 0,
+    );
+
+    expect(plan.progress, closeTo(0.3105, 0.0001));
+    expect(plan.progressPercent, '31.1%');
+  });
+
+  test('条目总数为 0 时不除零', () {
+    const StudyPlan plan = StudyPlan(
+      deckName: '空集',
+      algorithm: 'SM-2',
+      totalItems: 0,
+      activatedItems: 0,
+      dueItems: 0,
+      newItems: 0,
+      secondsPerItem: 13,
+    );
+
+    expect(plan.progress, 0);
+    expect(plan.progressPercent, '0.0%');
+  });
+}