initial commit: Go version of SMS Receiver with fixed template rendering

- Implemented all core features from Python version
- Fixed int64/int type compatibility in template functions
- Added login authentication, SMS receiving, statistics, logs
- Independent database: sms_receiver_go.db
- Fixed frontend display issues for message list and statistics

config/config.go

@@ -0,0 +1,142 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/spf13/viper"
+)
+
+type Config struct {
+	App       AppConfig       `mapstructure:"app"`
+	Server    ServerConfig    `mapstructure:"server"`
+	Security  SecurityConfig  `mapstructure:"security"`
+	SMS       SMSConfig       `mapstructure:"sms"`
+	Database  DatabaseConfig  `mapstructure:"database"`
+	Timezone  string          `mapstructure:"timezone"`
+	APITokens []APIToken      `mapstructure:"api_tokens"`
+}
+
+type AppConfig struct {
+	Name    string `mapstructure:"name"`
+	Version string `mapstructure:"version"`
+}
+
+type ServerConfig struct {
+	Host  string `mapstructure:"host"`
+	Port  int    `mapstructure:"port"`
+	Debug bool   `mapstructure:"debug"`
+}
+
+type SecurityConfig struct {
+	Enabled          bool   `mapstructure:"enabled"`
+	Username         string `mapstructure:"username"`
+	Password         string `mapstructure:"password"`
+	SessionLifetime  int    `mapstructure:"session_lifetime"`
+	SecretKey        string `mapstructure:"secret_key"`
+	SignVerify       bool   `mapstructure:"sign_verify"`
+	SignMaxAge       int64  `mapstructure:"sign_max_age"`
+}
+
+type SMSConfig struct {
+	MaxMessages  int  `mapstructure:"max_messages"`
+	AutoCleanup  bool `mapstructure:"auto_cleanup"`
+	CleanupDays  int  `mapstructure:"cleanup_days"`
+}
+
+type DatabaseConfig struct {
+	Path string `mapstructure:"path"`
+}
+
+type APIToken struct {
+	Name    string `mapstructure:"name"`
+	Token   string `mapstructure:"token"`
+	Secret  string `mapstructure:"secret"`
+	Enabled bool   `mapstructure:"enabled"`
+}
+
+var cfg *Config
+
+func Load(configPath string) (*Config, error) {
+	viper.SetConfigFile(configPath)
+	viper.SetConfigType("yaml")
+
+	// 允许环境变量覆盖
+	viper.AutomaticEnv()
+
+	if err := viper.ReadInConfig(); err != nil {
+		return nil, fmt.Errorf("读取配置文件失败: %w", err)
+	}
+
+	cfg = &Config{}
+	if err := viper.Unmarshal(cfg); err != nil {
+		return nil, fmt.Errorf("解析配置文件失败: %w", err)
+	}
+
+	return cfg, nil
+}
+
+func Get() *Config {
+	return cfg
+}
+
+// GetSessionLifetimeDuration 返回会话 lifetime 为 duration
+func (c *Config) GetSessionLifetimeDuration() time.Duration {
+	return time.Duration(c.Security.SessionLifetime) * time.Second
+}
+
+// GetSignMaxAgeDuration 返回签名最大有效期
+func (c *Config) GetSignMaxAgeDuration() time.Duration {
+	return time.Duration(c.Security.SignMaxAge) * time.Millisecond
+}
+
+// GetServerAddress 返回服务器地址
+func (c *Config) GetServerAddress() string {
+	return fmt.Sprintf("%s:%d", c.Server.Host, c.Server.Port)
+}
+
+// GetTokenByName 根据名称获取 Token 配置
+func (c *Config) GetTokenByName(name string) *APIToken {
+	for i := range c.APITokens {
+		if c.APITokens[i].Name == name && c.APITokens[i].Enabled {
+			return &c.APITokens[i]
+		}
+	}
+	return nil
+}
+
+// GetTokenByValue 根据 token 值获取配置
+func (c *Config) GetTokenByValue(token string) *APIToken {
+	for i := range c.APITokens {
+		if c.APITokens[i].Token == token && c.APITokens[i].Enabled {
+			return &c.APITokens[i]
+		}
+	}
+	return nil
+}
+
+// Save 保存配置到文件
+func (c *Config) Save(path string) error {
+	viper.Set("app", c.App)
+	viper.Set("server", c.Server)
+	viper.Set("security", c.Security)
+	viper.Set("sms", c.SMS)
+	viper.Set("database", c.Database)
+	viper.Set("timezone", c.Timezone)
+	viper.Set("api_tokens", c.APITokens)
+
+	return viper.WriteConfigAs(path)
+}
+
+// LoadDefault 加载默认配置文件
+func LoadDefault() (*Config, error) {
+	configPath := "config.yaml"
+	if _, err := os.Stat(configPath); os.IsNotExist(err) {
+		// 尝试查找上层目录
+		if _, err := os.Stat("../config.yaml"); err == nil {
+			configPath = "../config.yaml"
+		}
+	}
+	return Load(configPath)
+}