docs: update README assets and add Lighthouse report

[CodingWithJiro]

Description

Updated the repository presentation by adding the README.md preview assets, replaced outdated portfolio screenshots, and adding the latest Lighthouse performance report.

Changes

README

• Updated the repository preview image.
• Updated the preview image link.
• Updated the Lighthouse report screenshot.
• Updated the Lighthouse report URL.

Assets

• Removed the Next.js development UI from preview images.
• Added the latest Lighthouse report screenshot.
• Added the Lighthouse report PDF.

Screenshot

Old Preview	New Preview

Notes for Reviewers

• This PR focuses on improving the repository's documentation and presentation.
• I removed the previous screenshots since it included the Next.js dev UI.
• The latest Lighthouse report has been included for reference and documentation.
• I don't like the current preview so I changed the mockup design.
• I will probably change it in the future too if it gets too stale.

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Project	Deployment	Actions	Updated (UTC)
elmarchavez	Ready	Preview, Comment	Jul 27, 2026 10:16am

[CodingWithJiro]

In a team setting, this PR would await senior developer approval.
For this solo project, I’ll proceed with merging after review.