Add category taxonomy and navigation integration

Implements Issue #35 with category snippets, article category routing, category-aware templates, and category RSS feeds with tests.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

apps/blog/feeds.py

@@ -3,7 +3,7 @@ from django.contrib.syndication.views import Feed
 from django.shortcuts import get_object_or_404
 from taggit.models import Tag
 
-from apps.blog.models import ArticlePage
+from apps.blog.models import ArticlePage, Category
 
 
 class AllArticlesFeed(Feed):
@@ -48,3 +48,15 @@ class TagArticlesFeed(AllArticlesFeed):
 
     def items(self, obj):
         return ArticlePage.objects.live().filter(tags=obj).order_by("-first_published_at")[:20]
+
+
+class CategoryArticlesFeed(AllArticlesFeed):
+    def get_object(self, request, category_slug: str):
+        self.request = request
+        return get_object_or_404(Category, slug=category_slug)
+
+    def title(self, obj):
+        return f"No Hype AI — {obj.name}"
+
+    def items(self, obj):
+        return ArticlePage.objects.live().filter(category=obj).order_by("-first_published_at")[:20]