feat: 性能优化 + Bug修复 + 搜索增强

- expo-image 替换 RN Image（VideoCard/LiveCard/BigVideoCard/CommentItem，recyclingKey）
- DanmakuList Animated.Value 对象池，减少 GC 压力
- FlatList 性能参数：windowSize=7 / maxToRenderPerBatch=6 / removeClippedSubviews
- bilibili.ts 请求去重（getVideoDetail/getPlayUrl）
- SESSDATA 迁移至 expo-secure-store（utils/secureStorage.ts，启动自动迁移）
- 主题系统扩展：新增 sheetBg/modalBg/modalText/placeholder/iconDefault/danger 等 token
- 多组件深色模式适配：DownloadSheet/LivePlayer/NativeVideoPlayer/DownloadProgressBtn/CommentItem/LoginModal
- 搜索页增强：搜索建议 + 热搜榜（hooks/useSearch.ts + app/search.tsx）
- LoginModal 修复轮询竞态（cancelled flag + try-catch）
- 修复 downloads.tsx 冗余三元表达式

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "jkvideo",
-  "version": "1.0.6",
+  "version": "1.0.14",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "jkvideo",
-      "version": "1.0.6",
+      "version": "1.0.14",
       "dependencies": {
         "@dr.pogodin/react-native-static-server": "^0.26.0",
         "@expo/vector-icons": "^15.0.2",
@@ -19,12 +19,14 @@
         "expo-constants": "~55.0.9",
         "expo-dev-client": "~55.0.11",
         "expo-file-system": "~55.0.10",
+        "expo-image": "~55.0.6",
         "expo-intent-launcher": "~55.0.9",
         "expo-linear-gradient": "~55.0.8",
         "expo-media-library": "~55.0.10",
         "expo-network": "~55.0.9",
         "expo-router": "~55.0.4",
         "expo-screen-orientation": "~55.0.8",
+        "expo-secure-store": "~55.0.9",
         "expo-status-bar": "~55.0.4",
         "expo-system-ui": "~55.0.9",
         "pako": "^2.1.0",
@@ -5295,6 +5297,15 @@
         "react-native": "*"
       }
     },
+    "node_modules/expo-secure-store": {
+      "version": "55.0.9",
+      "resolved": "https://registry.npmjs.org/expo-secure-store/-/expo-secure-store-55.0.9.tgz",
+      "integrity": "sha512-TIPGjM73LKlebpXwgAu/yL7lNWr6RQYmFw3vgYHOqLFYQMpsBqkQmopovbNX3c/0+RCE9KZlLAkcz8r6detILQ==",
+      "license": "MIT",
+      "peerDependencies": {
+        "expo": "*"
+      }
+    },
     "node_modules/expo-server": {
       "version": "55.0.6",
       "resolved": "https://registry.npmjs.org/expo-server/-/expo-server-55.0.6.tgz",