Version: 0.4.4.dev.260307

feat: 🚀 增强会话管理与缓存机制

* 会话 ID 空值兜底，若 `conversation_id` 为空时自动生成 UUID
* 在响应头写入 `X-Conversation-ID`，供前端使用，保持同一会话状态

perf: ⚡ 会话状态缓存优化

* 当缓存未命中但 DB 已确认/创建会话后，调用 `SetConversationStatus` 回写 Redis
* 缓存写回失败时记录日志，不中断聊天主流程，确保业务流畅性

fix: 🐛 修复历史消息顺序问题与编译错误

* 修复历史消息顺序问题，保证返回的 N 条历史消息按时间正序喂给模型

  * 通过反转 `created_at desc` 查询结果的切片，确保模型输入顺序正确
* 修复 `fmt.Errorf` 参数不匹配问题，修正编译错误
* 整理 `agent-cache.go` 为标准 UTF-8 编码，避免 Go 编译报错 `invalid UTF-8 encoding`

feat: 🛠️ 独立构建 MCP 服务器

* 使用 `Codex` 构建独立于后端的 MCP 服务器，简化与 Codex 的协作
* 通过该服务器方便 Codex 直接测试和查看 Redis 与 MySQL 中的数据

infra/smartflow-mcp-server/internal/tools/mysql_readonly.go

@@ -0,0 +1,95 @@
+package tools
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/LoveLosita/smartflow/infra/smartflow-mcp-server/internal/security"
+	"github.com/LoveLosita/smartflow/infra/smartflow-mcp-server/internal/store"
+)
+
+type MySQLReadOnlyTool struct {
+	client    *store.MySQLClient
+	validator *security.SQLValidator
+	maxRows   int
+}
+
+func NewMySQLReadOnlyTool(client *store.MySQLClient, validator *security.SQLValidator, maxRows int) *MySQLReadOnlyTool {
+	return &MySQLReadOnlyTool{client: client, validator: validator, maxRows: maxRows}
+}
+
+func (t *MySQLReadOnlyTool) Name() string {
+	return "mysql_query_readonly"
+}
+
+func (t *MySQLReadOnlyTool) Description() string {
+	return "Execute read-only SQL on MySQL. Only SELECT/SHOW/DESCRIBE/EXPLAIN are allowed."
+}
+
+func (t *MySQLReadOnlyTool) InputSchema() map[string]any {
+	return map[string]any{
+		"type": "object",
+		"properties": map[string]any{
+			"sql": map[string]any{
+				"type":        "string",
+				"description": "Read-only SQL statement",
+			},
+			"params": map[string]any{
+				"type":        "array",
+				"description": "Optional bind parameters",
+				"items": map[string]any{
+					"type": []string{"string", "number", "boolean", "null"},
+				},
+			},
+		},
+		"required":             []string{"sql"},
+		"additionalProperties": false,
+	}
+}
+
+func (t *MySQLReadOnlyTool) Execute(ctx context.Context, args map[string]any) (map[string]any, error) {
+	rawSQL, ok := args["sql"].(string)
+	if !ok || rawSQL == "" {
+		return nil, fmt.Errorf("sql must be a non-empty string")
+	}
+	if err := t.validator.ValidateReadOnlySQL(rawSQL); err != nil {
+		return nil, err
+	}
+
+	params, err := normalizeParams(args["params"])
+	if err != nil {
+		return nil, err
+	}
+
+	res, err := t.client.QueryReadOnly(ctx, rawSQL, params, t.maxRows)
+	if err != nil {
+		return nil, err
+	}
+	return map[string]any{
+		"columns":    res.Columns,
+		"rows":       res.Rows,
+		"rowCount":   res.RowCount,
+		"truncated":  res.Truncated,
+		"durationMs": res.DurationMs,
+	}, nil
+}
+
+func normalizeParams(raw any) ([]any, error) {
+	if raw == nil {
+		return nil, nil
+	}
+	arr, ok := raw.([]any)
+	if !ok {
+		return nil, fmt.Errorf("params must be an array")
+	}
+	out := make([]any, 0, len(arr))
+	for _, item := range arr {
+		switch v := item.(type) {
+		case string, float64, bool, nil:
+			out = append(out, v)
+		default:
+			return nil, fmt.Errorf("params contains unsupported type")
+		}
+	}
+	return out, nil
+}