diff --git a/internal/freedoc/create_document_pg_test.go b/internal/freedoc/create_document_pg_test.go
new file mode 100644
index 00000000..d43329c2
--- /dev/null
+++ b/internal/freedoc/create_document_pg_test.go
@@ -0,0 +1,124 @@
+package freedoc_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"chat-agent-system/internal/db"
+	"chat-agent-system/internal/docrevision"
+	"chat-agent-system/internal/freedoc"
+)
+
+func TestCreateDocument_PG_ClientKeyIdempotentAndLedgerSurvivesNewService(t *testing.T) {
+	dsn := db.SkipIfNoTestDatabaseURL(t)
+	ctx := context.Background()
+	pool, err := pgxpool.New(ctx, dsn)
+	require.NoError(t, err)
+	defer pool.Close()
+
+	var hasClientKey bool
+	err = pool.QueryRow(ctx, `
+		SELECT EXISTS (
+			SELECT 1 FROM information_schema.columns
+			WHERE table_name = 'freeform_documents' AND column_name = 'client_key'
+		)
+	`).Scan(&hasClientKey)
+	if err != nil || !hasClientKey {
+		t.Skip("freeform_documents.client_key missing; migrate 00029 required")
+	}
+	var hasVersions bool
+	_ = pool.QueryRow(ctx, `
+		SELECT EXISTS (
+			SELECT 1 FROM information_schema.tables WHERE table_name = 'document_versions'
+		)
+	`).Scan(&hasVersions)
+	if !hasVersions {
+		t.Skip("document_versions missing; migrate 00028 required")
+	}
+
+	userID := 91001
+	clientKey := fmt.Sprintf("doc-upload-pg-%d", time.Now().UnixNano())
+	rev1 := docrevision.NewService(pool)
+	svc1 := freedoc.NewService(pool, nil)
+	svc1.SetDocRevision(rev1)
+
+	detail, err := svc1.CreateDocument(ctx, userID, freedoc.CreateFreeformDocRequest{
+		ProjectID:       1,
+		Title:           "PG上传规格",
+		ContentMarkdown: "# PG上传规格\n\n基线正文\n",
+		Space:           "my_private",
+		ClientKey:       clientKey,
+	})
+	require.NoError(t, err)
+	docID := detail.Document.DocID
+	require.NotEmpty(t, docID)
+	require.NotNil(t, detail.Document.ClientKey)
+	assert.Equal(t, clientKey, *detail.Document.ClientKey)
+	assert.NotContains(t, detail.Document.SourceContentSHA256, "doc-upload")
+	assert.Len(t, detail.Document.SourceContentSHA256, 64)
+
+	// client_key 幂等：同一 owner+key 返回同一 doc
+	again, err := svc1.CreateDocument(ctx, userID, freedoc.CreateFreeformDocRequest{
+		ProjectID:       1,
+		Title:           "PG上传规格",
+		ContentMarkdown: "# PG上传规格\n\n基线正文\n",
+		ClientKey:       clientKey,
+	})
+	require.NoError(t, err)
+	assert.Equal(t, docID, again.Document.DocID)
+
+	st1, err := rev1.GetRevisionState(ctx, docID)
+	require.NoError(t, err)
+	assert.GreaterOrEqual(t, st1.CurrentVersionNo, 1)
+
+	patched := "# PG上传规格\n\n基线正文\n\nPG人工修订\n"
+	_, err = rev1.CommitHumanRevision(ctx, docrevision.HumanRevisionRequest{
+		DocID: docID, Markdown: patched,
+		ExpectedHeadSnapshot: &st1.HeadSnapshotID, ExpectedRevisionNo: &st1.HeadRevisionNo,
+		IdempotencyKey: fmt.Sprintf("pg-upload-patch-%d", time.Now().UnixNano()),
+		ActorUserID:    int64(userID), LifecycleState: "drafting", ProjectID: 1,
+	})
+	require.NoError(t, err)
+	_, err = svc1.UpdateDocument(ctx, userID, docID, freedoc.UpdateFreeformDocRequest{
+		ContentMarkdown: &patched,
+		ChangeSummary:   "pg patch",
+	})
+	require.NoError(t, err)
+
+	// 新 Service 实例：client_key 仍可解析，revision-state 与正文可恢复
+	rev2 := docrevision.NewService(pool)
+	svc2 := freedoc.NewService(pool, nil)
+	svc2.SetDocRevision(rev2)
+
+	byKey, err := svc2.CreateDocument(ctx, userID, freedoc.CreateFreeformDocRequest{
+		ProjectID:       1,
+		Title:           "ignored",
+		ContentMarkdown: "# ignored\n",
+		ClientKey:       clientKey,
+	})
+	require.NoError(t, err)
+	assert.Equal(t, docID, byKey.Document.DocID)
+
+	st2, err := rev2.GetRevisionState(ctx, docID)
+	require.NoError(t, err, "revision-state must hydrate after new Service")
+	assert.GreaterOrEqual(t, st2.HeadRevisionNo, 1)
+
+	got, err := svc2.GetDocument(ctx, userID, docID)
+	require.NoError(t, err)
+	assert.Contains(t, got.Content, "PG人工修订")
+
+	t.Cleanup(func() {
+		_, _ = pool.Exec(context.Background(), `DELETE FROM freeform_document_versions WHERE doc_id=$1`, docID)
+		_, _ = pool.Exec(context.Background(), `DELETE FROM freeform_documents WHERE doc_id=$1`, docID)
+		_, _ = pool.Exec(context.Background(), `DELETE FROM document_change_events WHERE doc_id=$1`, docID)
+		_, _ = pool.Exec(context.Background(), `DELETE FROM document_versions WHERE doc_id=$1`, docID)
+		_, _ = pool.Exec(context.Background(), `DELETE FROM document_snapshots WHERE doc_id=$1`, docID)
+		_, _ = pool.Exec(context.Background(), `DELETE FROM document_access_audit WHERE doc_id=$1`, docID)
+	})
+}
diff --git a/internal/freedoc/create_document_test.go b/internal/freedoc/create_document_test.go
new file mode 100644
index 00000000..c1203163
--- /dev/null
+++ b/internal/freedoc/create_document_test.go
@@ -0,0 +1,83 @@
+package freedoc_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"chat-agent-system/internal/docrevision"
+	"chat-agent-system/internal/freedoc"
+)
+
+func TestCreateDocument_ClientKeyIdempotentAndBootstrapsLedger(t *testing.T) {
+	ctx := context.Background()
+	rev := docrevision.NewService(nil)
+	svc := freedoc.NewService(nil, nil)
+	svc.SetDocRevision(rev)
+
+	detail, err := svc.CreateDocument(ctx, 42, freedoc.CreateFreeformDocRequest{
+		ProjectID:       7,
+		Title:           "超声探头规格.pdf",
+		ContentMarkdown: "# 超声探头规格\n\n上传正文基线\n",
+		Space:           "my_private",
+		ClientKey:       "doc-upload-1789263145197-0",
+	})
+	require.NoError(t, err)
+	require.NotNil(t, detail)
+	assert.True(t, len(detail.Document.DocID) > 0)
+	assert.True(t, detail.Document.DocID[:8] == "doc-free" || detail.Document.DocID[:9] == "doc-free-")
+	require.NotNil(t, detail.Document.ClientKey)
+	assert.Equal(t, "doc-upload-1789263145197-0", *detail.Document.ClientKey)
+	assert.Equal(t, "freeform", detail.Document.GovernanceMode)
+	// source_content_sha256 must remain content fingerprint — never client_key prefix
+	assert.NotContains(t, detail.Document.SourceContentSHA256, "doc-upload")
+	assert.NotContains(t, detail.Document.SourceContentSHA256, "client_key")
+	assert.Len(t, detail.Document.SourceContentSHA256, 64)
+
+	st, err := rev.GetRevisionState(ctx, detail.Document.DocID)
+	require.NoError(t, err)
+	assert.GreaterOrEqual(t, st.CurrentVersionNo, 1)
+
+	again, err := svc.CreateDocument(ctx, 42, freedoc.CreateFreeformDocRequest{
+		ProjectID:       7,
+		Title:           "超声探头规格.pdf",
+		ContentMarkdown: "# 超声探头规格\n\n上传正文基线\n",
+		ClientKey:       "doc-upload-1789263145197-0",
+	})
+	require.NoError(t, err)
+	assert.Equal(t, detail.Document.DocID, again.Document.DocID)
+
+	otherUser, err := svc.CreateDocument(ctx, 99, freedoc.CreateFreeformDocRequest{
+		ProjectID:       7,
+		Title:           "他人同名键",
+		ContentMarkdown: "# other\n",
+		ClientKey:       "doc-upload-1789263145197-0",
+	})
+	require.NoError(t, err)
+	assert.NotEqual(t, detail.Document.DocID, otherUser.Document.DocID)
+}
+
+func TestCreateDocument_RejectsEmptyContent(t *testing.T) {
+	svc := freedoc.NewService(nil, nil)
+	_, err := svc.CreateDocument(context.Background(), 1, freedoc.CreateFreeformDocRequest{
+		ProjectID: 1, Title: "x", ContentMarkdown: "   ",
+	})
+	assert.ErrorIs(t, err, freedoc.ErrInvalidParam)
+}
+
+func TestCreateDocument_RequiresProjectIDAndPrivateSpace(t *testing.T) {
+	svc := freedoc.NewService(nil, nil)
+	_, err := svc.CreateDocument(context.Background(), 1, freedoc.CreateFreeformDocRequest{
+		ProjectID: 0, Title: "x", ContentMarkdown: "# x\n",
+	})
+	assert.ErrorIs(t, err, freedoc.ErrInvalidParam)
+	assert.Contains(t, err.Error(), "project_id")
+
+	_, err = svc.CreateDocument(context.Background(), 1, freedoc.CreateFreeformDocRequest{
+		ProjectID: 1, Title: "x", ContentMarkdown: "# x\n", Space: "project_shared",
+	})
+	assert.ErrorIs(t, err, freedoc.ErrInvalidParam)
+	assert.Contains(t, err.Error(), "my_private")
+}
diff --git a/internal/freedoc/service.go b/internal/freedoc/service.go
index 5afa94b6..b464e837 100644
--- a/internal/freedoc/service.go
+++ b/internal/freedoc/service.go
@@ -6,14 +6,15 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"strings"
 	"sync"
 	"time"
 
-	"github.com/jackc/pgx/v5"
-	"github.com/jackc/pgx/v5/pgxpool"
 	"chat-agent-system/internal/ctxmgr"
 	"chat-agent-system/internal/docrevision"
 	"chat-agent-system/internal/replyexport"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
 )
 
 type Service struct {
@@ -25,15 +26,18 @@ type Service struct {
 	memDocs     map[string]*FreeformDocument
 	memVersions map[string][]*FreeformDocumentVersion
 	memAudit    []map[string]any
+	// memClientKeys mirrors PG uq_freeform_owner_client_key (owner|client_key → doc_id)
+	memClientKeys map[string]string
 }
 
 func NewService(pool *pgxpool.Pool, ctxMgr *ctxmgr.ContextManager) *Service {
 	return &Service{
-		pool:        pool,
-		ctxMgr:      ctxMgr,
-		memDocs:     make(map[string]*FreeformDocument),
-		memVersions: make(map[string][]*FreeformDocumentVersion),
-		memAudit:    make([]map[string]any, 0),
+		pool:          pool,
+		ctxMgr:        ctxMgr,
+		memDocs:       make(map[string]*FreeformDocument),
+		memVersions:   make(map[string][]*FreeformDocumentVersion),
+		memAudit:      make([]map[string]any, 0),
+		memClientKeys: make(map[string]string),
 	}
 }
 
@@ -232,6 +236,207 @@ func (s *Service) CreateFromMessage(ctx context.Context, userID int, req CreateF
 	}, false, nil
 }
 
+func clientKeyLookup(userID int, clientKey string) string {
+	return fmt.Sprintf("%d|%s", userID, strings.TrimSpace(clientKey))
+}
+
+func (s *Service) bootstrapLedger(ctx context.Context, userID int, detail *FreeformDocDetail) {
+	if s == nil || s.docRev == nil || detail == nil {
+		return
+	}
+	md := detail.Content
+	if strings.TrimSpace(md) == "" {
+		return
+	}
+	_, _ = s.docRev.EnsureBootstrap(ctx, docrevision.BootstrapRequest{
+		DocID:          detail.Document.DocID,
+		Kind:           "freeform",
+		Markdown:       md,
+		ProjectID:      int64(detail.Document.ProjectID),
+		LifecycleState: "drafting",
+		Actor: docrevision.ActorSnapshot{
+			DisplayName: "freeform-owner",
+			Role:        "owner",
+		},
+	})
+}
+
+func (s *Service) findByClientKeyPG(ctx context.Context, userID int, clientKey string) (*FreeformDocDetail, error) {
+	var docID string
+	err := s.pool.QueryRow(ctx, `
+		SELECT doc_id FROM freeform_documents
+		WHERE owner_user_id = $1 AND client_key = $2 AND is_deleted = FALSE
+		LIMIT 1
+	`, userID, clientKey).Scan(&docID)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	return s.GetDocument(ctx, userID, docID)
+}
+
+// CreateDocument 直接创建自由文档（上传附件 / 自定义正文的服务端事实源）。
+// client_key 持久化于 freeform_documents.client_key，与 owner 唯一；禁止污染 source_content_sha256。
+// 创建后立即 EnsureBootstrap 版本账本，使 revision-state 可读、PATCH 可持久化。
+func (s *Service) CreateDocument(ctx context.Context, userID int, req CreateFreeformDocRequest) (*FreeformDocDetail, error) {
+	title := strings.TrimSpace(req.Title)
+	content := req.ContentMarkdown
+	if title == "" {
+		return nil, fmt.Errorf("%w: title required", ErrInvalidParam)
+	}
+	if strings.TrimSpace(content) == "" {
+		return nil, fmt.Errorf("%w: content_markdown required", ErrInvalidParam)
+	}
+	space := strings.TrimSpace(req.Space)
+	if space == "" {
+		space = "my_private"
+	}
+	// Direct create is upload/private registration only; project_shared must go through ShareDocument.
+	if space != "my_private" {
+		return nil, fmt.Errorf("%w: direct create only allows my_private; use share API", ErrInvalidParam)
+	}
+	projectID := req.ProjectID
+	if projectID <= 0 {
+		return nil, fmt.Errorf("%w: project_id required", ErrInvalidParam)
+	}
+	clientKey := strings.TrimSpace(req.ClientKey)
+	var clientKeyPtr *string
+	if clientKey != "" {
+		clientKeyPtr = &clientKey
+	}
+
+	if clientKey != "" {
+		if s.pool != nil {
+			existing, err := s.findByClientKeyPG(ctx, userID, clientKey)
+			if err != nil {
+				return nil, err
+			}
+			if existing != nil {
+				return existing, nil
+			}
+		} else {
+			s.mu.RLock()
+			existingID := s.memClientKeys[clientKeyLookup(userID, clientKey)]
+			s.mu.RUnlock()
+			if existingID != "" {
+				return s.GetDocument(ctx, userID, existingID)
+			}
+		}
+	}
+
+	contentHash := computeSHA256(content)
+	docID := fmt.Sprintf("doc-free-%d-%d", time.Now().UnixNano(), userID)
+	now := time.Now()
+
+	if s.pool != nil {
+		tx, err := s.pool.Begin(ctx)
+		if err != nil {
+			return nil, err
+		}
+		defer tx.Rollback(ctx)
+
+		_, err = tx.Exec(ctx, `
+			INSERT INTO freeform_documents (
+				doc_id, project_id, owner_user_id, source_message_id, source_content_sha256,
+				client_key, title, governance_mode, space, legacy_version_id, current_sha256,
+				is_deleted, created_at, updated_at
+			) VALUES ($1, $2, $3, NULL, $4, $5, $6, 'freeform', $7, 1, $4, FALSE, $8, $8)
+		`, docID, projectID, userID, contentHash, clientKeyPtr, title, space, now)
+		if err != nil {
+			// Unique race: another request inserted the same owner+client_key
+			if clientKey != "" {
+				if existing, findErr := s.findByClientKeyPG(ctx, userID, clientKey); findErr == nil && existing != nil {
+					return existing, nil
+				}
+			}
+			return nil, fmt.Errorf("insert freeform_doc: %w", err)
+		}
+		_, err = tx.Exec(ctx, `
+			INSERT INTO freeform_document_versions (
+				doc_id, version_no, content_sha256, content_markdown, created_by, change_summary, created_at
+			) VALUES ($1, 1, $2, $3, $4, '上传附件注册', $5)
+		`, docID, contentHash, content, userID, now)
+		if err != nil {
+			return nil, fmt.Errorf("insert version: %w", err)
+		}
+		_, err = tx.Exec(ctx, `
+			INSERT INTO document_access_audit (doc_id, user_id, action, success, created_at)
+			VALUES ($1, $2, 'create_upload', TRUE, $3)
+		`, docID, userID, now)
+		if err != nil {
+			return nil, fmt.Errorf("insert audit: %w", err)
+		}
+		if err := tx.Commit(ctx); err != nil {
+			return nil, err
+		}
+
+		detail := &FreeformDocDetail{
+			Document: FreeformDocument{
+				DocID:               docID,
+				ProjectID:           projectID,
+				OwnerUserID:         userID,
+				SourceContentSHA256: contentHash,
+				ClientKey:           clientKeyPtr,
+				Title:               title,
+				GovernanceMode:      "freeform",
+				Space:               space,
+				CurrentVersionID:    1,
+				CurrentSHA256:       contentHash,
+				IsDeleted:           false,
+				CreatedAt:           now,
+				UpdatedAt:           now,
+			},
+			Content: content,
+		}
+		s.bootstrapLedger(ctx, userID, detail)
+		return detail, nil
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if clientKey != "" {
+		if existingID := s.memClientKeys[clientKeyLookup(userID, clientKey)]; existingID != "" {
+			doc := s.memDocs[existingID]
+			versions := s.memVersions[existingID]
+			cur := ""
+			if len(versions) > 0 {
+				cur = versions[len(versions)-1].ContentMarkdown
+			}
+			if doc != nil {
+				return &FreeformDocDetail{Document: *doc, Content: cur}, nil
+			}
+		}
+	}
+	newDoc := &FreeformDocument{
+		DocID:               docID,
+		ProjectID:           projectID,
+		OwnerUserID:         userID,
+		SourceContentSHA256: contentHash,
+		ClientKey:           clientKeyPtr,
+		Title:               title,
+		GovernanceMode:      "freeform",
+		Space:               space,
+		CurrentVersionID:    1,
+		CurrentSHA256:       contentHash,
+		IsDeleted:           false,
+		CreatedAt:           now,
+		UpdatedAt:           now,
+	}
+	s.memDocs[docID] = newDoc
+	s.memVersions[docID] = []*FreeformDocumentVersion{{
+		ID: 1, DocID: docID, VersionNo: 1, ContentSHA256: contentHash,
+		ContentMarkdown: content, CreatedBy: userID, ChangeSummary: "上传附件注册", CreatedAt: now,
+	}}
+	if clientKey != "" {
+		s.memClientKeys[clientKeyLookup(userID, clientKey)] = docID
+	}
+	detail := &FreeformDocDetail{Document: *newDoc, Content: content}
+	s.bootstrapLedger(ctx, userID, detail)
+	return detail, nil
+}
+
 // GetDocument 获取文档详情及内容，严格执行私密与共享访问控制
 func (s *Service) GetDocument(ctx context.Context, userID int, docID string) (*FreeformDocDetail, error) {
 	if docID == "" {
diff --git a/internal/freedoc/service_db_test.go b/internal/freedoc/service_db_test.go
index 22eb1861..1d71f721 100644
--- a/internal/freedoc/service_db_test.go
+++ b/internal/freedoc/service_db_test.go
@@ -6,12 +6,12 @@ import (
 	"testing"
 	"time"
 
-	"github.com/jackc/pgx/v5/pgxpool"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 	"chat-agent-system/internal/config"
 	"chat-agent-system/internal/ctxmgr"
 	"chat-agent-system/internal/freedoc"
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestFreeformDoc_DatabaseIntegration(t *testing.T) {
diff --git a/internal/freedoc/service_test.go b/internal/freedoc/service_test.go
index 0879b50a..006c8fae 100644
--- a/internal/freedoc/service_test.go
+++ b/internal/freedoc/service_test.go
@@ -4,10 +4,10 @@ import (
 	"context"
 	"testing"
 
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 	"chat-agent-system/internal/ctxmgr"
 	"chat-agent-system/internal/freedoc"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestFreeformDocService_LifecycleAndACL(t *testing.T) {
diff --git a/internal/freedoc/types.go b/internal/freedoc/types.go
index e15e1c90..78b5cfcd 100644
--- a/internal/freedoc/types.go
+++ b/internal/freedoc/types.go
@@ -15,20 +15,21 @@ var (
 
 // FreeformDocument 自由私密/共享文档元数据
 type FreeformDocument struct {
-	DocID                string     `json:"doc_id"`
-	ProjectID            int        `json:"project_id"`
-	OwnerUserID          int        `json:"owner_user_id"`
-	SourceMessageID      *int64     `json:"source_message_id,omitempty"`
-	SourceContentSHA256  string     `json:"source_content_sha256"`
-	Title                string     `json:"title"`
-	GovernanceMode       string     `json:"governance_mode"` // 恒为 'freeform'
-	Space                string     `json:"space"`           // 'my_private' | 'project_shared' | 'trash'
-	CurrentVersionID     int        `json:"current_version_id"`
-	CurrentSHA256        string     `json:"current_sha256"`
-	IsDeleted            bool       `json:"is_deleted"`
-	DeletedAt            *time.Time `json:"deleted_at,omitempty"`
-	CreatedAt            time.Time  `json:"created_at"`
-	UpdatedAt            time.Time  `json:"updated_at"`
+	DocID               string     `json:"doc_id"`
+	ProjectID           int        `json:"project_id"`
+	OwnerUserID         int        `json:"owner_user_id"`
+	SourceMessageID     *int64     `json:"source_message_id,omitempty"`
+	SourceContentSHA256 string     `json:"source_content_sha256"`
+	ClientKey           *string    `json:"client_key,omitempty"`
+	Title               string     `json:"title"`
+	GovernanceMode      string     `json:"governance_mode"` // 恒为 'freeform'
+	Space               string     `json:"space"`           // 'my_private' | 'project_shared' | 'trash'
+	CurrentVersionID    int        `json:"current_version_id"`
+	CurrentSHA256       string     `json:"current_sha256"`
+	IsDeleted           bool       `json:"is_deleted"`
+	DeletedAt           *time.Time `json:"deleted_at,omitempty"`
+	CreatedAt           time.Time  `json:"created_at"`
+	UpdatedAt           time.Time  `json:"updated_at"`
 }
 
 // FreeformDocumentVersion 自由文档历史版本快照
@@ -70,12 +71,14 @@ type CreateFromMessageRequest struct {
 	ExpectedSHA256 string `json:"expected_sha256,omitempty"`
 }
 
-// CreateFreeformDocRequest 直接创建空白/自定义自由文档请求
+// CreateFreeformDocRequest 直接创建空白/自定义自由文档请求（上传附件即时注册事实源）
 type CreateFreeformDocRequest struct {
 	ProjectID       int    `json:"project_id"`
 	Title           string `json:"title"`
 	ContentMarkdown string `json:"content_markdown"`
 	Space           string `json:"space,omitempty"` // 默认 'my_private'
+	// ClientKey 可选幂等键（如 doc-upload-{ts}-{idx}），同用户重复提交返回已有文档
+	ClientKey string `json:"client_key,omitempty"`
 }
 
 // UpdateFreeformDocRequest 更新自由文档请求