fix: tabBar 跟随主题切换

pages.json 默认配色改为亮色（白底紫字）
App.vue + settings.vue 用 uni.setTabBarStyle() 动态切换
暗色模式：黑底紫字（rgba(255,255,255,0.25) / #b388ff / #08080f）
亮色模式：白底紫字（rgba(0,0,0,0.35) / #7c4dff / #ffffff）

frontend/ai-dimension/src/App.vue

@@ -27,7 +27,7 @@ function initTheme() {
 
 function applyTheme(theme) {
   try {
-    // H5 环境直接操作 document
+    // H5 环境：操作 document class
     const root = document.documentElement
     if (theme === 'dark') {
       root.classList.add('theme-dark')
@@ -37,7 +37,31 @@ function applyTheme(theme) {
       root.classList.add('theme-light')
     }
   } catch (e) {
-    // 小程序环境：document 不存在，直接忽略
+    // 小程序环境：document 不存在
+  }
+  // 小程序 tabBar 原生组件同步切换
+  applyTabBarTheme(theme)
+}
+
+function applyTabBarTheme(theme) {
+  try {
+    if (theme === 'dark') {
+      uni.setTabBarStyle({
+        color: 'rgba(255,255,255,0.25)',
+        selectedColor: '#b388ff',
+        backgroundColor: '#08080f',
+        borderStyle: 'black'
+      })
+    } else {
+      uni.setTabBarStyle({
+        color: 'rgba(0,0,0,0.35)',
+        selectedColor: '#7c4dff',
+        backgroundColor: '#ffffff',
+        borderStyle: 'white'
+      })
+    }
+  } catch (e) {
+    // H5 环境 setTabBarStyle 可能不支持
   }
 }
 </script>

frontend/ai-dimension/src/pages.json

@@ -18,21 +18,21 @@
     {"path": "pages/profile/profile", "style": {"navigationBarTitleText": "我的", "navigationStyle": "custom"}}
   ],
   "globalStyle": {
-    "navigationBarTextStyle": "white",
+    "navigationBarTextStyle": "black",
     "navigationBarTitleText": "宇之然AI维度",
-    "navigationBarBackgroundColor": "#050508",
+    "navigationBarBackgroundColor": "#f5f5f7",
-    "backgroundColor": "#050508",
+    "backgroundColor": "#f5f5f7",
-    "backgroundColorTop": "#050508",
+    "backgroundColorTop": "#f5f5f7",
-    "backgroundColorBottom": "#050508",
+    "backgroundColorBottom": "#f5f5f7",
     "app-plus": {
-      "background": "#050508"
+      "background": "#f5f5f7"
     }
   },
   "tabBar": {
-    "color": "rgba(255,255,255,0.25)",
+    "color": "rgba(0,0,0,0.35)",
-    "selectedColor": "#b388ff",
+    "selectedColor": "#7c4dff",
-    "backgroundColor": "#08080f",
+    "backgroundColor": "#ffffff",
-    "borderStyle": "black",
+    "borderStyle": "white",
     "list": [
       {"pagePath": "pages/index/index", "text": "探索"},
       {"pagePath": "pages/chat/chat", "text": "问答"},

frontend/ai-dimension/src/pages/settings/settings.vue

@@ -99,9 +99,19 @@ function applyTheme(theme) {
       root.classList.remove('theme-dark')
       root.classList.add('theme-light')
     }
-  } catch (e) {
+  } catch (e) {}
-    // mini-program 忽略
+  // tabBar 同步
-  }
+  applyTabBarTheme(theme)
+}
+
+function applyTabBarTheme(theme) {
+  try {
+    if (theme === 'dark') {
+      uni.setTabBarStyle({ color: 'rgba(255,255,255,0.25)', selectedColor: '#b388ff', backgroundColor: '#08080f', borderStyle: 'black' })
+    } else {
+      uni.setTabBarStyle({ color: 'rgba(0,0,0,0.35)', selectedColor: '#7c4dff', backgroundColor: '#ffffff', borderStyle: 'white' })
+    }
+  } catch (e) {}
 }
 
 function showAbout() {