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

backend_api_python/migrations/init.sql

@@ -18,6 +18,7 @@ CREATE TABLE IF NOT EXISTS qd_users (
     vip_expires_at TIMESTAMP,              -- VIP过期时间
     email_verified BOOLEAN DEFAULT FALSE,  -- 邮箱是否已验证
     referred_by INTEGER,                   -- 邀请人ID
+    notification_settings TEXT DEFAULT '', -- 用户通知配置 JSON (telegram_chat_id, default_channels等)
     last_login_at TIMESTAMP,
     created_at TIMESTAMP DEFAULT NOW(),
     updated_at TIMESTAMP DEFAULT NOW()