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/ai/openai_client.go

@@ -1,8 +1,13 @@
 package ai
 
 import (
+	"context"
+	"fmt"
+	"strings"
+	"sync"
 	"time"
 
+	"github.com/google/uuid"
 	"github.com/mlogclub/simple/sqls"
 	openai "github.com/openai/openai-go/v3"
 	"github.com/openai/openai-go/v3/option"
@@ -10,6 +15,7 @@ import (
 	"code.tczkiot.com/wlw/ai-agent/internal/models"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/enums"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/errorsx"
+	"code.tczkiot.com/wlw/ai-agent/internal/pkg/tracex"
 	"code.tczkiot.com/wlw/ai-agent/internal/repositories"
 )
 
@@ -21,13 +27,102 @@ func newOpenAIClient(config models.AIConfig) openai.Client {
 	if config.TimeoutMS > 0 {
 		opts = append(opts, option.WithRequestTimeout(time.Duration(config.TimeoutMS)*time.Millisecond))
 	}
+	if config.HTTPClient != nil {
+		opts = append(opts, option.WithHTTPClient(config.HTTPClient))
+	}
 	if config.MaxRetryCount >= 0 {
 		opts = append(opts, option.WithMaxRetries(config.MaxRetryCount))
 	}
-
 	return openai.NewClient(opts...)
 }
 
+type platformAIRequestScopeContextKey struct{}
+type platformAIRequestPurposeContextKey struct{}
+
+type platformAIRequestScope struct {
+	base string
+	mu   sync.Mutex
+	next map[string]uint64
+}
+
+// WithPlatformAIRequestScope binds a persisted business operation identity to
+// platform AI calls. Recreating a scope with the same base during recovery
+// reproduces the same purpose/ordinal request IDs, while one live scope gives
+// every logical upstream call a distinct ordinal.
+func WithPlatformAIRequestScope(ctx context.Context, base string) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	base = strings.TrimSpace(base)
+	if base == "" {
+		return ctx
+	}
+	return context.WithValue(ctx, platformAIRequestScopeContextKey{}, &platformAIRequestScope{
+		base: base,
+		next: make(map[string]uint64),
+	})
+}
+
+// WithPlatformAIRequestPurpose separates otherwise identical calls belonging
+// to different stages such as retrieval and document indexing.
+func WithPlatformAIRequestPurpose(ctx context.Context, purpose string) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	purpose = strings.TrimSpace(purpose)
+	if purpose == "" {
+		return ctx
+	}
+	return context.WithValue(ctx, platformAIRequestPurposeContextKey{}, purpose)
+}
+
+func ensurePlatformAIRequestScope(ctx context.Context) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	if scope, _ := ctx.Value(platformAIRequestScopeContextKey{}).(*platformAIRequestScope); scope != nil && strings.TrimSpace(scope.base) != "" {
+		return ctx
+	}
+	if requestID := tracex.RequestIDFromContext(ctx); requestID != "" {
+		return WithPlatformAIRequestScope(ctx, "request:"+requestID)
+	}
+	// No durable business identity is available (for example a one-off debug
+	// call), so create one scope for the public operation. Callers with recovery
+	// semantics must bind their persisted identity explicitly.
+	return WithPlatformAIRequestScope(ctx, "operation:"+uuid.NewString())
+}
+
+func nextPlatformAIRequestID(ctx context.Context, defaultPurpose string) string {
+	ctx = ensurePlatformAIRequestScope(ctx)
+	scope, _ := ctx.Value(platformAIRequestScopeContextKey{}).(*platformAIRequestScope)
+	purpose, _ := ctx.Value(platformAIRequestPurposeContextKey{}).(string)
+	purpose = strings.TrimSpace(purpose)
+	if purpose == "" {
+		purpose = strings.TrimSpace(defaultPurpose)
+	}
+	if purpose == "" {
+		purpose = "request"
+	}
+
+	scope.mu.Lock()
+	scope.next[purpose]++
+	ordinal := scope.next[purpose]
+	scope.mu.Unlock()
+	return uuid.NewSHA1(uuid.NameSpaceOID, []byte(fmt.Sprintf("%s:purpose:%s:call:%d", scope.base, purpose, ordinal))).String()
+}
+
+// platformRequestOptions creates one deterministic idempotency key for one
+// logical upstream call. SDK retries reuse these options. A later call in the
+// same operation gets the next ordinal; recovery recreates the same sequence.
+func platformRequestOptions(ctx context.Context, config models.AIConfig, purpose string) []option.RequestOption {
+	if !config.Platform {
+		return nil
+	}
+	return []option.RequestOption{
+		option.WithHeader("X-AI-Request-ID", nextPlatformAIRequestID(ctx, purpose)),
+	}
+}
+
 func GetEnabledAIConfig(modelType enums.AIModelType) (*models.AIConfig, error) {
 	item := repositories.AIConfigRepository.GetEnabled(sqls.DB(), modelType)
 	if item == nil {