Add dorveille article and full Hugo site scaffold

- content/dorveille.md: 'On the Craft of Invisible Systems'
- assets/css/: ASW layer system (00-reset through 09-landing + Open Props)
- layouts/: baseof, single, list, index — semantic HTML, no classes
- hugo.toml: baseURL asw.trentuna.com, PostCSS + minify pipeline
- package.json: postcss-import, postcss-custom-media, cssnano
- .gitignore: excludes public/, node_modules, build artifacts

Site builds to public/ via hugo --minify. nginx serves public/ statically.

postcss.config.js

@@ -0,0 +1,7 @@
+module.exports = {
+  plugins: [
+    require('postcss-import'),
+    require('postcss-custom-media'),
+    require('cssnano')({ preset: 'default' })
+  ]
+}