feat: use collections and add frontmatter

source/screens/demo/layouts.njk

@@ -1,6 +1,10 @@
-<!-- layouts.page -->
+---
+title: Layouts
+tags:
+  - index
+---
 {% set pageBase = "../" %}
-{% set pageId = "layouts" %}
+{% set pageId = page.fileSlug %}
 
 {% extends "demo/_main.njk" %}
 
@@ -10,6 +14,7 @@
 {% endblock %}
 
 {% block main %}
+<!-- {{ page.fileSlug }}.page -->
   <div class="temp_layer">
     <!-- <div class="exp_overlay_btn exp_help_btn"> <span class="span_solo">?</span> </div> -->
     {% include "hippie/partials/_body_nav.njk" %}