chore: adopt nuxt-ai-ready 2.0.0

[harlan-zw]

❓ Type of change

• 🧹 Chore
• ✨ New feature

📚 Description

v2 carries the fix for the soft 404 this site was serving on every .md URL, so /anything-that-does-not-exist.md now answers 404 with the guidance body instead of 200.

It also lands the ai-ready:markdown:source hook, which is wired up here. /gh/<owner>/<repo>/<name>.md used to render the page to HTML and convert it back; it now answers with the SKILL.md we already hold:

$ curl skilld.dev/gh/vercel-labs/skills/find-skills.md
---
name: find-skills
description: Helps users discover and install agent skills when they ask...
canonical_url: https://skilld.dev/gh/vercel-labs/skills/find-skills
---
# Find Skills

That also drops the internal HTML subrequest behind every .md request, which was two thirds of the site's edge 404s on 19 Aug.

Two things the upgrade forced. indexNow: false is gone from the config because v2 removed the feature; nothing here used it and ai_ready_indexnow_log holds no rows. And skill-md-probe moved from server/middleware into nitro.handlers, because v2 runs Accept negotiation earlier and a scanned middleware now loses the race for .md paths to the module's. Without the move the raw-layout redirect merged in #51 silently stopped firing.

🤖 AI disclosure: Harlan Agent Kit modified this description. My AI open-source policy.