fix(help-center): address codex/code-quality review on PR #132

- getCategoryDepth in category-tree.ts: the \`while (current && ...)\` had
  a useless truthiness check — \`current\` is provably defined after the
  early \`!start\` return. Drop the redundant guard and type \`current\`
  as \`T\` instead of \`T | undefined\`. (github-code-quality)
- Article canonical URL was built as \`\${baseUrl}/\${categorySlug}/\${articleSlug}\`,
  missing the \`/hc\` prefix — wrong for og:url and rel=canonical after
  the help center moved under the portal layout. Prepend \`/hc\`.
  (codex P2)
- restoreCategory now refuses to restore a child whose parent is still
  deleted, raising a new \`PARENT_DELETED\` ValidationError. Without this,
  restoring a child first left it pointing at a hidden parent and the
  category silently dropped out of the sidebar tree (which only roots
  from parentId === null). Admins must restore the ancestor chain from
  the top down. New tests cover both the refusal path and the happy
  path where the parent is already active. (codex P2)

Author: mortondev

apps/web/src/lib/server/domains/help-center/__tests__/help-center-service.test.ts

@@ -1125,6 +1125,47 @@ describe('restoreCategory', () => {
       code: 'RESTORE_EXPIRED',
     })
   })
+
+  it('refuses to restore a child under a still-deleted parent', async () => {
+    const recentDeletedAt = new Date(Date.now() - 5 * 24 * 60 * 60 * 1000)
+    mockCategoryFindFirst.mockResolvedValueOnce({
+      id: 'category_child' as HelpCenterCategoryId,
+      slug: 'child',
+      name: 'Child Category',
+      parentId: 'category_parent' as HelpCenterCategoryId,
+      deletedAt: recentDeletedAt,
+      createdAt: new Date('2024-01-01'),
+      updatedAt: new Date('2024-01-01'),
+    })
+    mockCategoryFindFirst.mockResolvedValueOnce({
+      id: 'category_parent' as HelpCenterCategoryId,
+      deletedAt: recentDeletedAt,
+    })
+    await expect(restoreCategory('category_child' as HelpCenterCategoryId)).rejects.toMatchObject({
+      code: 'PARENT_DELETED',
+    })
+  })
+
+  it('restores a child when its parent is already active', async () => {
+    const recentDeletedAt = new Date(Date.now() - 5 * 24 * 60 * 60 * 1000)
+    mockCategoryFindFirst.mockResolvedValueOnce({
+      id: 'category_child' as HelpCenterCategoryId,
+      slug: 'child',
+      name: 'Child Category',
+      parentId: 'category_parent' as HelpCenterCategoryId,
+      deletedAt: recentDeletedAt,
+      createdAt: new Date('2024-01-01'),
+      updatedAt: new Date('2024-01-01'),
+    })
+    mockCategoryFindFirst.mockResolvedValueOnce({
+      id: 'category_parent' as HelpCenterCategoryId,
+      deletedAt: null,
+    })
+    const { db } = await import('@/lib/server/db')
+    vi.mocked(db.update).mockReturnValueOnce(makeRestoredCategoryChain() as never)
+    const result = await restoreCategory('category_child' as HelpCenterCategoryId)
+    expect(result.deletedAt).toBeNull()
+  })
 })
 
 // ============================================================================

apps/web/src/lib/server/domains/help-center/category-tree.ts

@@ -70,9 +70,9 @@ export function getCategoryDepth<T extends CategoryLike>(flat: T[], id: string):
   const start = byId.get(id)
   if (!start) return 0
   let depth = 0
-  let current: T | undefined = start
+  let current: T = start
   const seen = new Set<string>()
-  while (current && current.parentId !== null) {
+  while (current.parentId !== null) {
     if (seen.has(current.id)) break
     seen.add(current.id)
     const parent = byId.get(current.parentId)

apps/web/src/lib/server/domains/help-center/help-center.service.ts

@@ -336,6 +336,23 @@ export async function restoreCategory(id: HelpCenterCategoryId): Promise<HelpCen
     )
   }
 
+  // Refuse to restore a child under a still-deleted parent — it would keep
+  // a non-null parentId to a hidden ancestor and drop out of the active
+  // sidebar tree (which only roots from parentId === null). Admins must
+  // restore the ancestor chain first.
+  if (category.parentId) {
+    const parent = await db.query.helpCenterCategories.findFirst({
+      where: eq(helpCenterCategories.id, category.parentId),
+      columns: { id: true, deletedAt: true },
+    })
+    if (parent?.deletedAt) {
+      throw new ValidationError(
+        'PARENT_DELETED',
+        'Restore the parent category first, then restore this one.'
+      )
+    }
+  }
+
   const [restored] = await db
     .update(helpCenterCategories)
     .set({ deletedAt: null, updatedAt: new Date() })

apps/web/src/routes/_portal/hc/$categorySlug/$articleSlug.tsx

@@ -46,7 +46,7 @@ export const Route = createFileRoute('/_portal/hc/$categorySlug/$articleSlug')({
 
     const baseUrl =
       ((portalMatch?.context as Record<string, any> | undefined)?.baseUrl as string) ?? ''
-    const canonicalUrl = `${baseUrl}/${params.categorySlug}/${params.articleSlug}`
+    const canonicalUrl = `${baseUrl}/hc/${params.categorySlug}/${params.articleSlug}`
 
     return {
       meta: [