Optimize website performance using Google PageSpeed recommendations

[Copilot]

PR Summary

Implements PageSpeed optimizations across all site pages to reduce render-blocking resources, improve resource loading priority, and enhance caching.

• Motivation: Address PageSpeed Insights recommendations for improved load times and user experience
• Main changes:
  • JavaScript: Added defer to all footer scripts (6 files) - eliminates render-blocking while preserving execution order
  • Resource hints: Preload critical CSS, preconnect to formspree.io
  • Images: Lazy loading for below-fold content, fetchpriority="high" + eager loading for hero banners, async decoding throughout
  • Service worker: Network-first caching strategy, expanded asset cache, proper error handling with event.waitUntil(), version bump to v2

Files modified: _includes/footer.html, _includes/head.html, _includes/tiles.html, _layouts/{page,mdpage,news}.html, sw.js

Coverage: All 10 HTML pages optimized with consistent defer (8+), lazy/eager loading, preload hints (4), and fetchpriority on banner images.

Preview Artifact

This PR triggers the Preview Build workflow.

• Download the preview-site artifact from the workflow run to inspect the generated site.

• To view locally: Extract the artifact and serve it with a local web server:

  # Extract the zip file, then run one of:
  python3 -m http.server 8000
  # or
  npx serve
  # or
  php -S localhost:8000

  Then browse to http://localhost:8000

• Note: Opening HTML files directly (file://) won't work correctly due to absolute paths.

• Internal and external link check logs are in the preview-link-check-logs artifact.

• Link checks are non-blocking; fix issues where practical before merge.

Image & Asset Guidelines

Only WebP images should be referenced in the site; originals (PNG/JPG/etc.) may be stored for provenance.

1. Always reference the .webp version in Markdown/HTML.

2. Originals can live alongside WebP conversions but must NOT be used directly in content.

3. Prefer descriptive, kebab-case filenames (e.g., joao-victor-paim.webp).

4. If adding a new image, convert to WebP first. Example conversion commands:

   # Using cwebp
   cwebp input.jpg -q 80 -o output.webp
   
   # Using ImageMagick
   magick input.png -quality 80 output.webp

5. Run the existing resize helper if appropriate:

   ./resize_images.sh

   (Ensure the script suits the new image before relying on it.)

Checks Before Requesting Review

• Jekyll preview build succeeds locally (bundle exec jekyll build).
• All referenced images are WebP (originals not directly referenced).
• All member/profile links verified.
• External links added are valid (ignore transient 429/timeout warnings unless persistent).
• No large binary files (>5MB) added without justification.

Follow-up / Deployment Notes

Users may need hard refresh (Ctrl+Shift+R) on first visit post-deploy to update from service worker v1 → v2. Cache cleanup is automatic.

Screenshots (If UI/Content Changes)

No visual changes - performance optimizations only. Validate via PageSpeed Insights post-deployment.

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Maintainers: Ensure branch protection requires only CI + Preview jobs, not production Pages deployment for PRs.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• pagespeed.web.dev
  • Triggering command: /usr/bin/curl curl -s REDACTED (dns block)
• www.googleapis.com
  • Triggering command: /usr/bin/curl curl -s REDACTED --64 -o em.o /tmp/ccX0PZZk.s (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Optimize website using Google's tools</issue_title>
<issue_description>Check this webpage and its recommendations to improve website https://pagespeed.web.dev/analysis/https-secquoia-github-io/</issue_description>

<agent_instructions>Make sure that every page in the website is optimized, not only the main one</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Optimize website using Google's tools #81

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