Migrate website to Hugo blog architecture with timeline posts and CI build workflow

[Copilot]

This PR converts the site from a legacy single-page/Jekyll-style setup into a Hugo-based blog and enables CI-based static build validation. It also decomposes README timeline content into dated posts using git history timestamps and applies a consistent tech-oriented presentation layer.

• Hugo site migration

  • Added Hugo project configuration (hugo.toml) with section permalinks and navigation.
  • Introduced reusable templates (layouts/_default/baseof.html, list.html, single.html) for section lists and article pages.
  • Reorganized content under Hugo conventions (content/posts, content/meetups, content/announcements, content/archives).

• README timeline → blog posts

  • Split major README announcement blocks into independent posts in content/posts/.
  • Assigned post dates from relevant git commit history (blame/log-based), preserving chronology.
  • Replaced hardcoded internal links with Hugo-aware references where appropriate (relref) to keep routing stable under future path changes.

• Visual style update (tech-focused)

  • Added custom stylesheet (assets/css/main.css) with dark gradient theme, card-based list layout, and sticky header.
  • Added accessibility-focused refinements (nav landmark labeling, clearer list-link readable names, decorative symbol handling for assistive tech).
  • Added fallback styling for browsers without backdrop-filter support.

• CI workflow enablement

  • Added GitHub Actions workflow (.github/workflows/hugo-ci.yml) to build the site with Hugo on PRs and default-branch pushes.
  • Pins Hugo setup via peaceiris/actions-hugo and runs a deterministic hugo --minify build step.

name: Hugo CI
on:
  push:
    branches: ["main", "master"]
  pull_request:

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: peaceiris/actions-hugo@v3
        with:
          hugo-version: '0.148.2'
          extended: true
      - run: hugo --minify

[lazyparser]

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