feat: Move notification settings to user profile and add i18n support

- Move notification config from system settings (.env) to user profile (database)
- Add user-specific notification settings API endpoints (GET/PUT /api/user/notification-settings)
- Add notification_settings column to qd_users table
- Update portfolio and trading-assistant to use profile notification settings
- Add notification settings UI in profile page with all channels (browser, telegram, email, phone, discord, webhook)
- Add i18n translations for notification settings in 10 languages
- Fix timestamp parsing in TradingRecords and portfolio (handle both ISO strings and Unix timestamps)
- Fix header icons alignment for mobile responsive layout
- Fix equity curve timestamp bug (handle datetime objects properly)
- Remove unused login.js exports and clean up user.js store
- Remove husky, commitlint and other dev dependencies
- Clean up env.example by removing user-specific notification params
- Update signal_notifier to prioritize user-specific tokens over global env vars

quantdinger_vue/src/components/SelectLang/index.less

@@ -14,9 +14,19 @@
 }
 
 .@{header-drop-down-prefix-cls} {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  height: @layout-header-height;
   line-height: @layout-header-height;
+  padding: 0 12px;
   vertical-align: top;
   cursor: pointer;
+  transition: all 0.3s;
+
+  &:hover {
+    background: rgba(0, 0, 0, 0.04);
+  }
 
   > i {
     font-size: 16px !important;
@@ -28,3 +38,10 @@
     }
   }
 }
+
+/* 手机端适配 */
+@media (max-width: 768px) {
+  .@{header-drop-down-prefix-cls} {
+    padding: 0 8px;
+  }
+}