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/bootstrap/db_test.go

@@ -1,11 +1,15 @@
 package bootstrap
 
 import (
-	"os"
-	"path/filepath"
 	"testing"
 
+	"code.tczkiot.com/wlw/ai-agent/internal/models"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/config"
+
+	"github.com/glebarez/sqlite"
+	"github.com/mlogclub/simple/sqls"
+	"gorm.io/gorm"
+	"gorm.io/gorm/schema"
 )
 
 func TestNewDialector(t *testing.T) {
@@ -15,18 +19,15 @@ func TestNewDialector(t *testing.T) {
 		dbType string
 		want   string
 	}{
-		{dbType: "sqlite", want: "sqlite"},
-		{dbType: "mysql", want: "mysql"},
 		{dbType: "postgres", want: "postgres"},
 		{dbType: "postgresql", want: "postgres"},
 		{dbType: " PostgreSQL ", want: "postgres"},
 	}
 
 	for _, tt := range cases {
-		tt := tt
 		t.Run(tt.dbType, func(t *testing.T) {
 			t.Parallel()
-			dialector, err := newDialector(config.DBConfig{Type: tt.dbType, DSN: ":memory:"})
+			dialector, err := newDialector(config.DBConfig{Type: tt.dbType, DSN: "postgres-dsn"})
 			if err != nil {
 				t.Fatalf("newDialector() error = %v", err)
 			}
@@ -37,69 +38,42 @@ func TestNewDialector(t *testing.T) {
 	}
 }
 
-func TestNewDialectorRejectsUnsupportedType(t *testing.T) {
+func TestNewDialectorRejectsRemovedAndUnsupportedTypes(t *testing.T) {
 	t.Parallel()
 
-	if _, err := newDialector(config.DBConfig{Type: "oracle"}); err == nil {
-		t.Fatal("newDialector() error = nil, want unsupported type error")
+	for _, dbType := range []string{"sqlite", "mysql", "oracle", ""} {
+		if _, err := newDialector(config.DBConfig{Type: dbType}); err == nil {
+			t.Fatalf("newDialector(%q) error = nil, want unsupported type error", dbType)
+		}
 	}
 }
 
-func TestSQLiteFilePath(t *testing.T) {
-	t.Parallel()
-
-	cases := []struct {
-		name string
-		dsn  string
-		want string
-	}{
-		{
-			name: "plain relative path",
-			dsn:  "./data/app.db",
-			want: "./data/app.db",
-		},
-		{
-			name: "file uri with query",
-			dsn:  "file:./data/app.db?_busy_timeout=5000",
-			want: "./data/app.db",
-		},
-		{
-			name: "memory dsn",
-			dsn:  "file::memory:?cache=shared",
-			want: "",
-		},
-		{
-			name: "memory alias",
-			dsn:  ":memory:",
-			want: "",
-		},
+func TestUseDatabaseSharesConnectionWithoutChangingHostNaming(t *testing.T) {
+	// SQLite remains only as a lightweight in-memory unit-test fixture. Runtime
+	// database initialization accepts PostgreSQL exclusively.
+	host, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{
+		NamingStrategy: schema.NamingStrategy{TablePrefix: "iot_"},
+	})
+	if err != nil {
+		t.Fatalf("gorm.Open() error = %v", err)
 	}
+	hostTable := host.NamingStrategy.TableName("Conversation")
 
-	for _, tt := range cases {
-		tt := tt
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-			if got := sqliteFilePath(tt.dsn); got != tt.want {
-				t.Fatalf("sqliteFilePath(%q) = %q, want %q", tt.dsn, got, tt.want)
-			}
-		})
-	}
-}
-
-func TestEnsureSQLiteDir(t *testing.T) {
-	t.Parallel()
-
-	baseDir := t.TempDir()
-	dbPath := filepath.Join(baseDir, "nested", "app.db")
-	dsn := "file:" + dbPath + "?_busy_timeout=5000"
-
-	if err := ensureSQLiteDir(dsn); err != nil {
-		t.Fatalf("ensureSQLiteDir() error = %v", err)
-	}
-
-	if info, err := os.Stat(filepath.Dir(dbPath)); err != nil {
-		t.Fatalf("os.Stat() error = %v", err)
-	} else if !info.IsDir() {
-		t.Fatalf("expected %q to be a directory", filepath.Dir(dbPath))
+	if err := UseDatabase(host, "iot_ai_"); err != nil {
+		t.Fatalf("UseDatabase() error = %v", err)
+	}
+	moduleDB := sqls.DB()
+	statement := &gorm.Statement{DB: moduleDB}
+	if err := statement.Parse(&models.Conversation{}); err != nil {
+		t.Fatalf("Statement.Parse() error = %v", err)
+	}
+	if statement.Schema.Table != "iot_ai_conversation" {
+		t.Fatalf("module table=%q want iot_ai_conversation", statement.Schema.Table)
+	}
+	if got := host.NamingStrategy.TableName("Conversation"); got != hostTable {
+		t.Fatalf("host table changed from %q to %q", hostTable, got)
+	}
+	if moduleDB.ConnPool != host.ConnPool {
+		t.Fatal("module database does not share the host connection pool")
 	}
 }