flatten monorepo, migrate off Vercel

- Remove penfield (split to own repo on Forgejo)
- Move www/ contents to root, rename to wynne.rs
- Swap @astrojs/vercel for @astrojs/node, upgrade to Astro 6
- Remove auth-astro/GitHub OAuth (TinyAuth at proxy layer)
- Remove Vercel deploy webhook
- Switch to local SQLite DB (drop Turso)
- Update generate-stats.js for new build output paths

www/astro.config.mjs

@@ -1,24 +0,0 @@
-import { defineConfig } from 'astro/config';
-import vercel from '@astrojs/vercel';
-import db from '@astrojs/db';
-import auth from 'auth-astro';
-import remarkDirective from 'remark-directive';
-import remarkGfm from 'remark-gfm';
-import remarkSlug from 'remark-slug';
-import remarkSmartypants from 'remark-smartypants';
-import remarkAside from './src/plugins/remark-aside.ts';
-
-export default defineConfig({
-  output: 'static',
-  adapter: vercel(),
-  integrations: [db(), auth()],
-  markdown: {
-    remarkPlugins: [
-      remarkGfm,
-      remarkDirective,
-      remarkAside,
-      remarkSlug,
-      remarkSmartypants
-    ]
-  }
-});