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

src/scripts/guestbook-sign.ts

@@ -0,0 +1,43 @@
+export function initGuestbookForm() {
+  const form = document.getElementById('guestbook-form') as HTMLFormElement | null;
+  if (!form) return;
+
+  const status = document.getElementById('guestbook-status')!;
+
+  form.addEventListener('submit', async (e) => {
+    e.preventDefault();
+    status.textContent = '';
+
+    const data = new FormData(form);
+    const name = (data.get('name') as string).trim();
+    const message = (data.get('message') as string).trim();
+    const url = (data.get('url') as string).trim() || null;
+
+    if (!name || !message) return;
+
+    const button = form.querySelector('button')!;
+    button.disabled = true;
+
+    try {
+      const res = await fetch('/api/guestbook', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ name, message, url }),
+      });
+
+      if (res.ok) {
+        status.textContent = ' thanks! pending approval.';
+        form.reset();
+      } else if (res.status === 429) {
+        status.textContent = ' too many requests, try later.';
+      } else {
+        const body = await res.json().catch(() => null);
+        status.textContent = body?.error ? ` ${body.error}` : ' error';
+      }
+    } catch {
+      status.textContent = ' failed';
+    } finally {
+      button.disabled = false;
+    }
+  });
+}