fix: resolve P1 backend consistency issues

server/db/mysql/tenant_groups.go

@@ -936,11 +936,16 @@ func (a *adapter) TenantGroupFileCreate(id t.TenantID, file *t.GroupFile) (*t.Gr
 	}
 	a.enrichGroupFileFromUpload(id, file)
 	now := t.TimeNow()
-	ctx, cancel := a.getContext()
+	ctx, cancel := a.getContextForTx()
 	if cancel != nil {
 		defer cancel()
 	}
-	_, err := a.db.ExecContext(ctx, `INSERT INTO im_group_files
+	tx, err := a.db.BeginTxx(ctx, nil)
+	if err != nil {
+		return nil, err
+	}
+	defer tx.Rollback()
+	_, err = tx.ExecContext(ctx, `INSERT INTO im_group_files
 		(group_file_id,topic,file_id,source_topic,source_seq,uploader_id,file_name,mime_type,file_type,file_size,status,idempotency_key,created_at,updated_at)
 		VALUES(?,?,?,?,?,?,?,?,?,?,?,?,?,?)
 		ON DUPLICATE KEY UPDATE
@@ -954,6 +959,29 @@ func (a *adapter) TenantGroupFileCreate(id t.TenantID, file *t.GroupFile) (*t.Gr
 	if err != nil && !isDupe(err) {
 		return nil, err
 	}
+	uploadID := strings.TrimSpace(file.FileID)
+	if dot := strings.IndexByte(uploadID, '.'); dot > 0 {
+		uploadID = uploadID[:dot]
+	}
+	if fid := t.ParseUid(uploadID); !fid.IsZero() {
+		if a.tenantScopedDB {
+			_, err = tx.ExecContext(ctx, `INSERT INTO im_filemsglinks(createdat,fileid,topic)
+				SELECT ?,?,? WHERE NOT EXISTS (
+					SELECT 1 FROM im_filemsglinks WHERE fileid=? AND topic=?)`,
+				now, decodeUID(fid), file.Topic, decodeUID(fid), file.Topic)
+		} else {
+			_, err = tx.ExecContext(ctx, `INSERT INTO im_filemsglinks(tenant_id,createdat,fileid,topic)
+				SELECT ?,?,?,? WHERE NOT EXISTS (
+					SELECT 1 FROM im_filemsglinks WHERE tenant_id=? AND fileid=? AND topic=?)`,
+				id, now, decodeUID(fid), file.Topic, id, decodeUID(fid), file.Topic)
+		}
+		if err != nil {
+			return nil, err
+		}
+	}
+	if err = tx.Commit(); err != nil {
+		return nil, err
+	}
 	created, err := a.groupFileByQuery(ctx, "SELECT * FROM im_group_files WHERE topic=? AND file_id=?", file.Topic, file.FileID)
 	if err != nil {
 		return nil, err