feat: vue-mobile => 完成会话聊天页面功能，增加主题切换功能

web/src/store/system.js

@@ -0,0 +1,11 @@
+import Storage from "good-storage";
+
+const MOBILE_THEME = "MOBILE_THEME"
+
+export function getMobileTheme() {
+    return Storage.get(MOBILE_THEME) ? Storage.get(MOBILE_THEME) : 'light'
+}
+
+export function setMobileTheme(theme) {
+    Storage.set(MOBILE_THEME, theme)
+}