refactor: remove Gorse integration and implement HotRank feature

- Removed Gorse-related configurations, handlers, and dependencies from the codebase.
- Introduced HotRank feature with configuration options for ranking posts based on recent activity.
- Updated application structure to support HotRank processing, including new caching mechanisms and database interactions.
- Cleaned up related DTOs and repository methods to reflect the removal of Gorse and the addition of HotRank functionality.

internal/config/config.go

@@ -22,13 +22,13 @@ type Config struct {
 	Log               LogConfig               `mapstructure:"log"`
 	RateLimit         RateLimitConfig         `mapstructure:"rate_limit"`
 	Upload            UploadConfig            `mapstructure:"upload"`
-	Gorse             GorseConfig             `mapstructure:"gorse"`
 	OpenAI            OpenAIConfig            `mapstructure:"openai"`
 	Email             EmailConfig             `mapstructure:"email"`
 	ConversationCache ConversationCacheConfig `mapstructure:"conversation_cache"`
 	GRPC              GRPCConfig              `mapstructure:"grpc"`
 	Casbin            CasbinConfig            `mapstructure:"casbin"`
 	Encryption        EncryptionConfig        `mapstructure:"encryption"`
+	HotRank           HotRankConfig           `mapstructure:"hot_rank"`
 }
 
 // Load 加载配置文件
@@ -97,14 +97,6 @@ func Load(configPath string) (*Config, error) {
 	viper.SetDefault("sensitive.replace_str", "***")
 	viper.SetDefault("audit.enabled", false)
 	viper.SetDefault("audit.provider", "local")
-	viper.SetDefault("gorse.enabled", false)
-	viper.SetDefault("gorse.address", "http://localhost:8087")
-	viper.SetDefault("gorse.api_key", "")
-	viper.SetDefault("gorse.dashboard", "http://localhost:8088")
-	viper.SetDefault("gorse.import_password", "")
-	viper.SetDefault("gorse.embedding_api_key", "")
-	viper.SetDefault("gorse.embedding_url", "https://api.littlelan.cn/v1/embeddings")
-	viper.SetDefault("gorse.embedding_model", "BAAI/bge-m3")
 	viper.SetDefault("openai.enabled", true)
 	viper.SetDefault("openai.base_url", "https://api.littlelan.cn/")
 	viper.SetDefault("openai.api_key", "")
@@ -152,6 +144,12 @@ func Load(configPath string) (*Config, error) {
 	viper.SetDefault("encryption.enabled", false)
 	viper.SetDefault("encryption.key", "")
 	viper.SetDefault("encryption.key_version", 1)
+	viper.SetDefault("hot_rank.enabled", true)
+	viper.SetDefault("hot_rank.refresh_interval_seconds", 300)
+	viper.SetDefault("hot_rank.top_n", 100)
+	viper.SetDefault("hot_rank.recent_window_hours", 168)
+	viper.SetDefault("hot_rank.recent_fetch_limit", 500)
+	viper.SetDefault("hot_rank.candidate_cap", 800)
 
 	if err := viper.ReadInConfig(); err != nil {
 		return nil, fmt.Errorf("failed to read config: %w", err)
@@ -203,13 +201,6 @@ func Load(configPath string) (*Config, error) {
 	cfg.Server.Host = getEnvOrDefault("APP_SERVER_HOST", cfg.Server.Host)
 	cfg.Server.Port, _ = strconv.Atoi(getEnvOrDefault("APP_SERVER_PORT", fmt.Sprintf("%d", cfg.Server.Port)))
 	cfg.Server.Mode = getEnvOrDefault("APP_SERVER_MODE", cfg.Server.Mode)
-	cfg.Gorse.Address = getEnvOrDefault("APP_GORSE_ADDRESS", cfg.Gorse.Address)
-	cfg.Gorse.APIKey = getEnvOrDefault("APP_GORSE_API_KEY", cfg.Gorse.APIKey)
-	cfg.Gorse.Dashboard = getEnvOrDefault("APP_GORSE_DASHBOARD", cfg.Gorse.Dashboard)
-	cfg.Gorse.ImportPassword = getEnvOrDefault("APP_GORSE_IMPORT_PASSWORD", cfg.Gorse.ImportPassword)
-	cfg.Gorse.EmbeddingAPIKey = getEnvOrDefault("APP_GORSE_EMBEDDING_API_KEY", cfg.Gorse.EmbeddingAPIKey)
-	cfg.Gorse.EmbeddingURL = getEnvOrDefault("APP_GORSE_EMBEDDING_URL", cfg.Gorse.EmbeddingURL)
-	cfg.Gorse.EmbeddingModel = getEnvOrDefault("APP_GORSE_EMBEDDING_MODEL", cfg.Gorse.EmbeddingModel)
 	cfg.OpenAI.BaseURL = getEnvOrDefault("APP_OPENAI_BASE_URL", cfg.OpenAI.BaseURL)
 	cfg.OpenAI.APIKey = getEnvOrDefault("APP_OPENAI_API_KEY", cfg.OpenAI.APIKey)
 	cfg.OpenAI.ModerationModel = getEnvOrDefault("APP_OPENAI_MODERATION_MODEL", cfg.OpenAI.ModerationModel)