Replace v1 with v2 codebase

Full rewrite: swap out the v1 framework (src/, controllers/, views/,
twig/, sass/, skeleton/) for the working v2 codebase from phpproject
(App/, novaconium/, public/).

App/pages/blog/second-post/index.twig

@@ -0,0 +1,26 @@
+{% extends layout %}
+
+{% import '_layout/icons.twig' as icons %}
+
+{% block title %}A Second Post{% endblock %}
+{% block description %}A second post at its own URL, showing that adding a new page under App/pages/blog/ needs nothing but a new directory.{% endblock %}
+
+{% block robots %}index, follow{% endblock %}
+{% block canonical %}{{ request_path|default('/') }}{% endblock %}
+
+{% block og_type %}article{% endblock %}
+{% block og_title %}{{ block('title') }}{% endblock %}
+{% block og_description %}{{ block('description') }}{% endblock %}
+{% block og_url %}{{ block('canonical') }}{% endblock %}
+
+{% block twitter_card %}summary{% endblock %}
+{% block twitter_title %}{{ block('title') }}{% endblock %}
+{% block twitter_description %}{{ block('description') }}{% endblock %}
+
+{% block blog_content %}
+    <h1>A Second Post</h1>
+
+    <p>A second post at its own URL — <code>App/pages/blog/second-post/index.twig</code>. Just another plain, sidecar-less directory under <code>App/pages/blog/</code>, same as <a class="icon-link" href="/blog/hello-world">{{ icons.book() }}Hello, World!</a> next to it. Adding a new post is nothing more than a new directory with an <code>index.twig</code> — no route to register, no repository entry to add.</p>
+
+    <p>Both posts are listed on <a class="icon-link" href="/blog">{{ icons.book() }}the blog index</a>, built by <code>App/pages/blog/index.php</code> — see <a class="icon-link" href="/admin/docs/routing">{{ icons.link() }}Routing</a> for how a URL maps to a directory in the first place.</p>
+{% endblock %}