feat(ui): 添加底部标签栏自定义配置功能和药物堆叠展示

- 新增底部标签栏配置页面，支持切换标签显示/隐藏和恢复默认设置
- 实现已服用药物的堆叠卡片展示，优化药物列表视觉层次
- 集成Redux状态管理底部标签栏配置，支持本地持久化
- 优化个人中心页面背景渐变效果，移除装饰性圆圈元素
- 更新启动页和应用图标为新的品牌视觉
- 药物详情页AI分析加载动画替换为Lottie动画
- 调整药物卡片圆角半径提升视觉一致性
- 新增多语言支持（中英文）用于标签栏配置界面

主要改进：
1. 用户可以自定义底部导航栏显示内容
2. 已完成的药物以堆叠形式展示，节省空间
3. 配置数据通过AsyncStorage持久化保存
4. 支持默认配置恢复功能

app/(tabs)/medications.tsx

@@ -1,6 +1,7 @@
 import CelebrationAnimation, { CelebrationAnimationRef } from '@/components/CelebrationAnimation';
 import { DateSelector } from '@/components/DateSelector';
 import { MedicationCard } from '@/components/medication/MedicationCard';
+import { TakenMedicationsStack } from '@/components/medication/TakenMedicationsStack';
 import { ThemedText } from '@/components/ThemedText';
 import { IconSymbol } from '@/components/ui/IconSymbol';
 import { MedicalDisclaimerSheet } from '@/components/ui/MedicalDisclaimerSheet';
@@ -189,6 +190,16 @@ export default function MedicationsScreen() {
     return medicationsWithImages.filter((item: any) => item.status === activeFilter);
   }, [activeFilter, medicationsWithImages]);
 
+  const activeMedications = useMemo(() => {
+    if (activeFilter !== 'all') return filteredMedications;
+    return filteredMedications.filter((item: any) => item.status !== 'taken' && item.status !== 'skipped');
+  }, [activeFilter, filteredMedications]);
+
+  const completedMedications = useMemo(() => {
+    if (activeFilter !== 'all') return [];
+    return filteredMedications.filter((item: any) => item.status === 'taken' || item.status === 'skipped');
+  }, [activeFilter, filteredMedications]);
+
   const counts = useMemo(() => {
     const taken = medicationsWithImages.filter((item: any) => item.status === 'taken').length;
     // "未服用"计数包含 missed（已错过）和 upcoming（待服用）
@@ -354,7 +365,8 @@ export default function MedicationsScreen() {
           </View>
         ) : (
           <View style={styles.cardsWrapper}>
-            {filteredMedications.map((item: any) => (
+            {/* 渲染未服用的药物 */}
+            {activeMedications.map((item: any) => (
               <MedicationCard
                 key={item.id}
                 medication={item}
@@ -364,6 +376,17 @@ export default function MedicationsScreen() {
                 onCelebrate={handleMedicationTakenCelebration}
               />
             ))}
+            
+            {/* 渲染已完成(服用/跳过)的药物堆叠 */}
+            {completedMedications.length > 0 && (
+              <TakenMedicationsStack
+                medications={completedMedications}
+                colors={colors}
+                selectedDate={selectedDate}
+                onOpenDetails={(item) => handleOpenMedicationDetails(item.medicationId)}
+                onCelebrate={handleMedicationTakenCelebration}
+              />
+            )}
           </View>
         )}
       </ScrollView>