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/hello-world/index.twig

@@ -0,0 +1,26 @@
+{% extends layout %}
+
+{% import '_layout/icons.twig' as icons %}
+
+{% block title %}Hello, World!{% endblock %}
+{% block description %}The first post on this blog — a plain sidecar-less page, like every other post here now.{% 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>Hello, World!</h1>
+
+    <p>The first post on this blog — a plain page at <code>App/pages/blog/hello-world/index.twig</code>, sidecar-less like <a class="icon-link" href="/blog/twig-syntax-guide">{{ icons.book() }}the Twig Syntax Guide</a> and the <a class="icon-link" href="/blog/style-guide">{{ icons.book() }}Style Guide</a>. Since it has no sidecar, it's rendered once and served as static HTML from <code>public/cache/blog/hello-world/index.html</code> on every later request — see <a class="icon-link" href="/admin/docs/caching">{{ icons.book() }}Static caching</a>.</p>
+
+    <p>This URL used to be backed by a wildcard <code>App/pages/blog/[slug]/</code> route pulling from a <code>Lib\PostRepository</code> class — a live demo of route-param capture. That mechanism (any single URL segment captured into <code>$params</code>) is still fully supported by the framework; see <a class="icon-link" href="/admin/docs/routing">{{ icons.link() }}Routing</a>. It just isn't what renders this particular post anymore, now that this post is fixed content rather than a stand-in for arbitrary slugs.</p>
+{% endblock %}