feat(i18n): add missing translations for trading-assistant modal

- Add step2Params and step3Signal translations
- Add execution mode related translations (signal/live)
- Add notification channel translations (browser/email/phone/telegram/discord/webhook)
- Add live trading config translations (savedCredential, credentialName, etc.)
- Add batch operation message translations (batchCreateSuccess, batchStart/Stop/Delete)
- Add placeholders for email, phone, telegram, discord, webhook inputs
- Add validation messages for email and notify channel
- Add strategy group translations (startAll, stopAll, deleteAll, symbolCount)
- Support both zh-CN (Simplified Chinese) and zh-TW (Traditional Chinese)

backend_api_python/app/utils/db.py

@@ -104,7 +104,9 @@ def _init_db_schema(conn):
     ensure_columns("qd_strategies_trading", {
         "market_category": "TEXT DEFAULT 'Crypto'",
         "execution_mode": "TEXT DEFAULT 'signal'",
-        "notification_config": "TEXT DEFAULT ''"
+        "notification_config": "TEXT DEFAULT ''",
+        "strategy_group_id": "TEXT DEFAULT ''",  # 策略组ID，批量创建的策略共享同一个组ID
+        "group_base_name": "TEXT DEFAULT ''"     # 策略组基础名称（用于显示）
     })
 
     # 2. 持仓表