fix: keep Archive script inside the HTML document

[y4ho0]

What changed

• Move the Archive filter script inside BaseLayout, so Astro emits it before </body> instead of after </html>.
• Extend the distribution verifier to reject missing closing </html> tags and non-whitespace content after the closing document element.

Why

The browser recovered from the malformed output and the empty Archive page appeared functional, but the production build placed its page script after the closing </html> tag. This is invalid document structure and was not covered by the existing output checks.

Impact

Archive behavior is unchanged. The generated page is now structurally valid, and future instances of trailing content after </html> will fail the build.

Validation

• npm run check
• npm test (10 passed)
• npm run build
• git diff --check
• Tidy/HTML parser check confirms no content remains after </html>
• Production preview of /archive/ renders without overflow or console errors