refactor: 将客服后端重构为宿主可嵌入模块

- 注入数据库、运行时配置、统一响应、文件存储和平台 AI 能力，补充业务读写工具与客户快捷操作契约。

- 移除模块内重复的组织、客户、工单、标签、技能、旧工作流、MCP 和迁移实现，将身份权限与业务主体交由宿主管理。

- 使用 libSQL 重构向量存储，并完善图片消息、访客身份、排队调度、企业微信和支持聊天页面。

- 统一 HTTP、DTO 与 WebSocket 的 snake_case 协议，补齐模块初始化、业务动作和公共载荷等回归测试。

internal/pkg/config/config_test.go

@@ -41,23 +41,18 @@ func TestLoadOverridesValuesFromEnvironment(t *testing.T) {
 	content := []byte(`server:
   port: 8083
 db:
-  type: sqlite
-  dsn: file:./data/app.db?_busy_timeout=5000
+  type: postgres
+  dsn: postgres-dsn
 storage:
   local:
     baseUrl: /storage
-mcp:
-  servers:
-    system:
-      endpoint: http://127.0.0.1:8083/api/mcp
 `)
 	if err := os.WriteFile(path, content, 0600); err != nil {
 		t.Fatalf("WriteFile() error = %v", err)
 	}
 	t.Setenv("AGENT_DESK_SERVER_PORT", "8090")
-	t.Setenv("AGENT_DESK_DB_DSN", "mysql-dsn")
+	t.Setenv("AGENT_DESK_DB_DSN", "postgres-override-dsn")
 	t.Setenv("AGENT_DESK_STORAGE_LOCAL_BASEURL", "/files")
-	t.Setenv("AGENT_DESK_MCP_SERVERS_SYSTEM_ENDPOINT", "http://127.0.0.1:8090/api/mcp")
 
 	cfg, err := Load(path)
 	if err != nil {
@@ -67,16 +62,48 @@ mcp:
 	if cfg.Server.Port != 8090 {
 		t.Fatalf("Server.Port=%d want 8090", cfg.Server.Port)
 	}
-	if cfg.DB.Type != "sqlite" {
-		t.Fatalf("DB.Type=%q want sqlite", cfg.DB.Type)
+	if cfg.DB.Type != "postgres" {
+		t.Fatalf("DB.Type=%q want postgres", cfg.DB.Type)
 	}
-	if cfg.DB.DSN != "mysql-dsn" {
-		t.Fatalf("DB.DSN=%q want mysql-dsn", cfg.DB.DSN)
+	if cfg.DB.DSN != "postgres-override-dsn" {
+		t.Fatalf("DB.DSN=%q want postgres-override-dsn", cfg.DB.DSN)
 	}
 	if cfg.Storage.Local.BaseURL != "/files" {
 		t.Fatalf("Storage.Local.BaseURL=%q want /files", cfg.Storage.Local.BaseURL)
 	}
-	if cfg.MCP.Servers["system"].Endpoint != "http://127.0.0.1:8090/api/mcp" {
-		t.Fatalf("MCP system endpoint=%q", cfg.MCP.Servers["system"].Endpoint)
+}
+
+func TestFromSettingsBuildsRuntimeConfig(t *testing.T) {
+	cfg, err := FromSettings(map[string]string{
+		"ai_agent_language":                      "en-US",
+		"ai_agent_storage_default":               "oss",
+		"ai_agent_storage_max_upload_size_mb":    "64",
+		"ai_agent_storage_oss_private":           "true",
+		"ai_vector_path":                         "/var/lib/agent-desk/vectors.db",
+		"ai_agent_wxwork_notify_to_users":        `[1,2,3]`,
+		"ai_agent_wxwork_notify_dedupe_interval": "900",
+	})
+	if err != nil {
+		t.Fatalf("FromSettings() error = %v", err)
+	}
+	if cfg.Language != "en-US" || cfg.Storage.Default != "oss" {
+		t.Fatalf("unexpected basic config: %+v", cfg)
+	}
+	if cfg.Storage.MaxUploadSizeMB != 64 || !cfg.Storage.OSS.Private {
+		t.Fatalf("unexpected storage config: %+v", cfg.Storage)
+	}
+	if cfg.VectorDB.Path != "/var/lib/agent-desk/vectors.db" {
+		t.Fatalf("VectorDB.Path=%q", cfg.VectorDB.Path)
+	}
+	if len(cfg.WxWork.Notify.ToUsers) != 3 || cfg.WxWork.Notify.DuplicateCheckInterval != 900 {
+		t.Fatalf("unexpected WeCom notify config: %+v", cfg.WxWork.Notify)
+	}
+}
+
+func TestFromSettingsRejectsInvalidValues(t *testing.T) {
+	if _, err := FromSettings(map[string]string{
+		"ai_agent_wxwork_notify_dedupe_interval": "not-a-number",
+	}); err == nil {
+		t.Fatal("FromSettings() error = nil, want invalid setting error")
 	}
 }