fix: ignore .docx dead links in VitePress build

[Copilot]

VitePress's dead link checker fails on links to .docx assets because it only validates HTML/markdown routes — even when the file physically exists. This caused the CI build to fail on a valid download link in recruit-v2-preview/02-declarative-agent/index.md.

Changes

• docs/.vitepress/config.mts — adds ignoreDeadLinks: [/\.docx$/] to suppress false-positive dead link errors for .docx asset references

export default defineConfig({
  title: "Agent Academy",
  base: "/agent-academy/",
  cleanUrls: true,
  ignoreDeadLinks: [/\.docx$/],
  // ...
});