Fix blank GitHub Pages deployment: set Vite base path, drop legacy HTML

[Copilot]

paranjayy.github.io/content-extractor rendered a white screen because Vite was emitting root-relative asset paths (/assets/...) while GitHub Pages serves the app under the /content-extractor/ sub-path — causing every JS/CSS/icon request to 404.

Changes

• app/vite.config.ts — add base: '/content-extractor/'

  export default defineConfig({
    plugins: [react(), tailwindcss()],
    base: '/content-extractor/',   // ← fixes asset paths for GH Pages
    ...
  })

  Vite now rewrites all asset references in the built index.html to /content-extractor/assets/....

• .github/workflows/deploy.yml — remove legacy HTML copy step
  The frontend/ directory (old standalone HTML tools) is no longer copied into _site/legacy/. The deploy artifact is now just app/dist/.

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.