fix(post,slug-tracker): correct ObjectId vs string comparisons

trackSlugChanges, updateById's category check, and checkRelated were
comparing mongoose ObjectId instances against string ids from request
bodies with === / !==, which is always false. The tracker bug produced
89 redundant slug_trackers in production; the related-check silently
disabled the self-relation guard.

Switch to String()-normalized comparisons, and harden createTracker to
upsert on (slug, type, targetId) so future regressions cannot duplicate.

Author: Innei

apps/core/src/modules/post/post.service.ts

@@ -176,7 +176,7 @@ export class PostService implements OnApplicationBootstrap {
     }
     if (
       newDocument.categoryId &&
-      oldDocument.categoryId !== newDocument.categoryId
+      String(oldDocument.categoryId) !== String(newDocument.categoryId)
     ) {
       return trackSlugChanges()
     }
@@ -269,7 +269,7 @@ export class PostService implements OnApplicationBootstrap {
 
     // 看看 category 改了没
     const { categoryId } = data
-    if (categoryId && categoryId !== oldDocument.categoryId) {
+    if (categoryId && String(categoryId) !== String(oldDocument.categoryId)) {
       const category = await this.categoryService.findCategoryById(
         categoryId as any as string,
       )
@@ -430,7 +430,7 @@ export class PostService implements OnApplicationBootstrap {
     }
 
     return relatedPosts.map((i) => {
-      if (i.related && (i.related as string[]).includes(data.id!)) {
+      if (i.related?.some((rel) => String(rel) === data.id)) {
         throw new BizException(ErrorCodeEnum.PostSelfRelation)
       }
       return i.id

apps/core/src/modules/slug-tracker/slug-tracker.service.ts

@@ -1,7 +1,9 @@
 import { Injectable } from '@nestjs/common'
 import type { ReturnModelType } from '@typegoose/typegoose'
+
 import type { ArticleTypeEnum } from '~/constants/article.constant'
 import { InjectModel } from '~/transformers/model.transformer'
+
 import { SlugTrackerModel } from './slug-tracker.model'
 
 @Injectable()
@@ -12,7 +14,11 @@ export class SlugTrackerService {
   ) {}
 
   createTracker(slug: string, type: ArticleTypeEnum, targetId: string) {
-    return this.slugTrackerModel.create({ slug, type, targetId })
+    return this.slugTrackerModel.updateOne(
+      { slug, type, targetId },
+      { $setOnInsert: { slug, type, targetId } },
+      { upsert: true },
+    )
   }
 
   findTrackerBySlug(slug: string, type: ArticleTypeEnum) {