DEV: Add backward compatibility for tag object arrays

What is the problem?

Discourse core PR #36678 changes `site.top_tags` and
`site.category_top_tags` from string arrays (e.g., `["support", "bug"]`)
to object arrays (e.g., `[{id: 12, name: "support", slug: "support"}]`).
This breaks the `PopularTags` component which filters and displays tags
as strings.

What is the solution?

Normalize the tags array by mapping and extracting names using
`typeof tag === "string" ? tag : tag.name` before filtering against
excluded tags. This ensures backward compatibility with both the old
string format and the new object format.

Author: tgxworld

javascripts/discourse/components/popular-tags.gjs

@@ -24,14 +24,17 @@ export default class PopularTags extends Component {
       [];
     const category = currentRoute.attributes?.category;
 
+    const normalizedTags = tags.map((tag) =>
+      typeof tag === "string" ? tag : tag.name
+    );
     if (excludedTags.length !== 0) {
-      this.topTags = tags
+      this.topTags = normalizedTags
         .filter((tag) => {
           return excludedTags.indexOf(tag) === -1;
         })
         .slice(0, count);
     } else {
-      this.topTags = (tags || []).slice(0, count);
+      this.topTags = normalizedTags.slice(0, count);
     }
 
     if (this.topTags.length === 0) {

spec/system/popular_tags_spec.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+RSpec.describe "Popular tags sidebar block", type: :system do
+  fab!(:tag) { Fabricate(:tag, name: "support") }
+  fab!(:topic) { Fabricate(:topic, tags: [tag]) }
+  fab!(:post) { Fabricate(:post, topic:) }
+  fab!(:user)
+
+  let!(:theme) { upload_theme_component }
+
+  before do
+    SiteSetting.tagging_enabled = true
+    sign_in(user)
+  end
+
+  it "loads theme without errors" do
+    visit("/")
+    expect(page).to have_no_css(".broken-theme-alert")
+  end
+end