refactor: migrate to /blog subdirectory

src/_pages/blog/feed/json.njk

@@ -0,0 +1,29 @@
+---
+# Metadata comes from _data/metadata.json
+permalink: /blog/feed/feed.json
+---
+{
+  "version": "https://jsonfeed.org/version/1.1",
+  "title": "{{ metadata.title }}",
+  "language": "{{ metadata.language }}",
+  "home_page_url": "{{ metadata.url | addPathPrefixToFullUrl }}",
+  "feed_url": "{{ permalink | htmlBaseUrl(metadata.url) }}",
+  "description": "{{ metadata.description }}",
+  "author": {
+    "name": "{{ metadata.author.name }}",
+    "url": "{{ metadata.author.url }}"
+  },
+  "items": [
+    {%- for article in collections.articles | reverse %}
+    {%- set absoluteArticleUrl = article.url | htmlBaseUrl(metadata.url) %}
+    {
+      "id": "{{ absoluteArticleUrl }}",
+      "url": "{{ absoluteArticleUrl }}",
+      "title": "{{ article.data.title }}",
+      "content_html": {% if article.templateContent %}{{ article.templateContent | transformWithHtmlBase(absoluteArticleUrl, article.url) | dump | safe }}{% else %}""{% endif %},
+      "date_published": "{{ article.date | dateToRfc3339 }}"
+    }
+    {% if not loop.last %},{% endif %}
+    {%- endfor %}
+  ]
+}