feat(public): serve /llms.txt at site root from content repo (#16)

The content repo now owns llms.txt — a single LLM-discoverability
manifest (https://llmstxt.org) documenting the seven service
endpoints, the anonymous-tier model, the claim flow, and the
conventions an LLM should follow when scripting against the
platform.

The prerender script gained one step: after building all
per-route HTML, it copies .content/llms.txt to dist/llms.txt
so any static host serves it at https://instanode.dev/llms.txt.

This pairs with the upstream content commit that added a
"Prompt for any LLM (no setup needed)" section to every one
of the 104 use-case .md files. Each prompt is paste-ready into
ChatGPT, Claude, or Gemini — the LLM reads llms.txt for context,
then generates a runnable script that drives the platform's HTTP
API with real curl calls. No MCP server, no API key, no install.

Verified: dist/llms.txt is 5.7 KB (the full manifest); every
one of the 104 /use-cases/<slug>/index.html pages contains the
new prompt section.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: mastermanas805

scripts/prerender.mjs

@@ -133,7 +133,21 @@ async function main() {
     written++
   }
 
-  // Step 5: clean up the SSR bundle — it's only needed during this script.
+  // Step 5: copy /llms.txt from the content repo to dist root. The
+  // llms.txt convention (https://llmstxt.org) expects the file at the
+  // domain root. Source of truth is .content/llms.txt — that lets the
+  // content repo author it like any other content file, and the
+  // dashboard build inlines it into dist/ for static hosting to serve.
+  const llmsSource = resolve(ROOT, '.content/llms.txt')
+  if (existsSync(llmsSource)) {
+    const llmsContent = await readFile(llmsSource, 'utf-8')
+    await writeFile(resolve(DIST, 'llms.txt'), llmsContent, 'utf-8')
+    console.log('prerender: copied llms.txt to dist root')
+  } else {
+    console.warn('prerender: no .content/llms.txt found, skipping')
+  }
+
+  // Step 6: clean up the SSR bundle — it's only needed during this script.
   // Leaving it in dist-ssr would inflate the GH Pages upload by ~400 KB.
   await rm(SSR_DIST, { recursive: true, force: true })