fix(dark): 调亮暗黑色调 + dock 跟随暗黑切换 + 图标文字放大

- theme/app.wxss: 暗黑背景 #0F0F12->#2C2C2E,卡片 #1C1C1E->#3A3A3C,
  bg-soft/border 同步提亮,拉开卡片与背景对比(原太黑看不到卡片)
- custom-tab-bar: dock 注册 wx.onThemeChange,系统切暗黑/明亮实时跟随
  (组件不在 getCurrentPages,app.js watchDarkMode 通知不到)
- custom-tab-bar: 新增 updateTheme,settings 手动切深色时通知 dock
- custom-tab-bar.wxss: dock 图标 44->50rpx,文字 20->23rpx,未激活
  opacity 0.5->0.7(更醒目)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

custom-tab-bar/index.js

@@ -62,6 +62,20 @@ Component({
       // Rebuild icons in case the user changed theme/dark mode since module load
       const theme = themeMod.getCurrentTheme()
       this.setData({ svgIcons: _buildIcons(theme.primary, _getInactiveColor()) })
+      // The custom tabBar isn't in getCurrentPages(), so app.js's
+      // watchDarkMode (which notifies pages) never reaches it. Listen for
+      // system theme changes ourselves so the dock flips dark/light live,
+      // not just on the next tab switch.
+      if (!this._themeChangeBound && typeof wx.onThemeChange === 'function') {
+        this._onThemeChange = () => {
+          themeMod.applyThemeToPage(this)
+          this.setData({ svgIcons: _buildIcons(themeMod.getCurrentTheme().primary, _getInactiveColor()) })
+        }
+        try {
+          wx.onThemeChange(this._onThemeChange)
+          this._themeChangeBound = true
+        } catch (e) {}
+      }
     }
   },
 
@@ -84,6 +98,12 @@ Component({
       ]
       if (index === this.data.selected) return
       wx.switchTab({ url: pages[index] })
+    },
+    // Called by settings.onSelectDarkMode - the dock isn't in
+    // getCurrentPages() so the page-loop there misses it.
+    updateTheme() {
+      themeMod.applyThemeToPage(this)
+      this.setData({ svgIcons: _buildIcons(themeMod.getCurrentTheme().primary, _getInactiveColor()) })
     }
   }
 })