feat(群级配置): 新增MySQL+Redis持久缓存并接入进群欢迎差异化配置

新增群级插件配置表与服务层，采用MySQL持久化+Redis长期缓存(TTL=-1)；后台新增群级插件配置管理页面与API，支持按群按插件维护JSON配置并在修改后同步回填MySQL和刷新Redis；已将群成员变更监控插件接入该配置，支持欢迎文案与卡片URL等按群差异化。

db/group_plugin_config_db.py

@@ -0,0 +1,132 @@
+# -*- coding: utf-8 -*-
+import json
+from typing import Any, Dict, List, Optional
+
+from loguru import logger
+
+from db.base import BaseDBOperator
+from db.connection import DBConnectionManager
+
+
+class GroupPluginConfigDBOperator(BaseDBOperator):
+    """群级插件配置数据库操作器。"""
+
+    def __init__(self, db_manager: DBConnectionManager):
+        super().__init__(db_manager)
+
+    def init_tables(self) -> bool:
+        """初始化群级插件配置表。"""
+        try:
+            return self.execute_update(
+                """
+                CREATE TABLE IF NOT EXISTS t_group_plugin_config (
+                    id BIGINT PRIMARY KEY AUTO_INCREMENT,
+                    group_id VARCHAR(100) NOT NULL,
+                    plugin_name VARCHAR(128) NOT NULL,
+                    config_key VARCHAR(128) NOT NULL DEFAULT 'default',
+                    config_json JSON NOT NULL,
+                    enabled TINYINT(1) NOT NULL DEFAULT 1,
+                    version INT NOT NULL DEFAULT 1,
+                    updated_by VARCHAR(100) NOT NULL DEFAULT 'system',
+                    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+                    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+                    UNIQUE KEY uk_group_plugin_key (group_id, plugin_name, config_key),
+                    INDEX idx_group_plugin (group_id, plugin_name),
+                    INDEX idx_plugin_name (plugin_name)
+                )
+                """
+            )
+        except Exception as e:
+            logger.error(f"初始化群级插件配置表失败: {e}")
+            return False
+
+    @staticmethod
+    def _parse_json_field(row: Dict[str, Any], key: str) -> None:
+        value = row.get(key)
+        if isinstance(value, str):
+            try:
+                row[key] = json.loads(value)
+            except Exception:
+                row[key] = {}
+        elif value is None:
+            row[key] = {}
+
+    def get_config(self, group_id: str, plugin_name: str, config_key: str = "default") -> Optional[Dict[str, Any]]:
+        """查询单条群级插件配置。"""
+        row = self.execute_query(
+            """
+            SELECT * FROM t_group_plugin_config
+            WHERE group_id = %s AND plugin_name = %s AND config_key = %s
+            LIMIT 1
+            """,
+            (group_id, plugin_name, config_key),
+            fetch_one=True,
+        )
+        if not row:
+            return None
+        self._parse_json_field(row, "config_json")
+        return row
+
+    def list_configs(self, group_id: str = "", plugin_name: str = "") -> List[Dict[str, Any]]:
+        """按条件列出配置。"""
+        where_sql = []
+        params = []
+        if group_id:
+            where_sql.append("group_id = %s")
+            params.append(group_id)
+        if plugin_name:
+            where_sql.append("plugin_name = %s")
+            params.append(plugin_name)
+        where_clause = f"WHERE {' AND '.join(where_sql)}" if where_sql else ""
+        rows = self.execute_query(
+            f"""
+            SELECT * FROM t_group_plugin_config
+            {where_clause}
+            ORDER BY updated_at DESC, id DESC
+            """,
+            tuple(params) if params else None,
+        ) or []
+        for row in rows:
+            self._parse_json_field(row, "config_json")
+        return rows
+
+    def upsert_config(
+        self,
+        group_id: str,
+        plugin_name: str,
+        config_key: str,
+        config_data: Dict[str, Any],
+        enabled: bool = True,
+        updated_by: str = "system",
+    ) -> bool:
+        """新增或更新配置。"""
+        return self.execute_update(
+            """
+            INSERT INTO t_group_plugin_config (
+                group_id, plugin_name, config_key, config_json, enabled, version, updated_by
+            ) VALUES (%s, %s, %s, %s, %s, 1, %s)
+            ON DUPLICATE KEY UPDATE
+                config_json = VALUES(config_json),
+                enabled = VALUES(enabled),
+                updated_by = VALUES(updated_by),
+                version = version + 1
+            """,
+            (
+                group_id,
+                plugin_name,
+                config_key,
+                json.dumps(config_data or {}, ensure_ascii=False),
+                1 if enabled else 0,
+                updated_by,
+            ),
+        )
+
+    def delete_config(self, group_id: str, plugin_name: str, config_key: str = "default") -> bool:
+        """删除指定配置。"""
+        return self.execute_update(
+            """
+            DELETE FROM t_group_plugin_config
+            WHERE group_id = %s AND plugin_name = %s AND config_key = %s
+            """,
+            (group_id, plugin_name, config_key),
+        )