feat: Implement the main backend HTTP API server for Codex Pool, including configuration, database initialization, and API routing.

backend/cmd/main.go

@@ -24,9 +24,11 @@ func main() {
 	fmt.Println()
 
 	// 确定数据目录
-	dataDir := "."
-	if _, err := os.Stat("data"); err == nil {
-		dataDir = "data"
+	dataDir := "data"
+	// 确保数据目录存在
+	if err := os.MkdirAll(dataDir, 0755); err != nil {
+		fmt.Printf("[警告] 创建数据目录失败: %v, 使用当前目录\n", err)
+		dataDir = "."
 	}
 
 	// 初始化数据库 (先于配置)