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/).

novaconium/config.php

@@ -0,0 +1,41 @@
+<?php
+
+// These are the framework defaults. A project overrides any subset of them
+// by creating App/config.php returning an array of just the keys it wants
+// to change — novaconium/bootstrap.php shallow-merges it over this file, the
+// same App-over-novaconium override pattern used for pages/ and lib/. This
+// file itself is not meant to be edited per-project.
+return [
+    // Ordered override roots: App/pages is checked first so a project can
+    // override any page, sidecar, or layout by placing one at the same
+    // relative path there; novaconium/pages supplies the framework defaults.
+    'pages_dirs' => [
+        __DIR__ . '/../App/pages',
+        __DIR__ . '/pages',
+    ],
+    'cache_dir' => __DIR__ . '/../public/cache',
+    'debug'     => true,
+
+    // Site name used as the default page title, og:site_name, and the
+    // footer copyright line in novaconium/pages/_layout/layout.twig.
+    'site_name' => 'Novaconium Website',
+
+    // Matomo analytics. Leave both empty (the default) to disable tracking
+    // entirely — the layout emits no tracking script at all in that case.
+    // Set both via App/config.php to enable, e.g.:
+    //   'matomo_url'     => 'https://matomo.example.com/',
+    //   'matomo_site_id' => '1',
+    'matomo_url'     => '',
+    'matomo_site_id' => '',
+
+    // Gates every /admin/* route (clear-cache, docs, and any future admin
+    // page) behind HTTP Basic Auth. Leave admin_password_hash empty (the
+    // default) to disable the gate entirely — matches this project's
+    // existing wide-open behavior until a project opts in. Generate a hash
+    // with: php -r "echo password_hash('yourpassword', PASSWORD_DEFAULT), PHP_EOL;"
+    // and set both via App/config.php, e.g.:
+    //   'admin_username'      => 'admin',
+    //   'admin_password_hash' => '$2y$10$...',
+    'admin_username'      => 'admin',
+    'admin_password_hash' => '',
+];