chore: point Pages to nested site URL

[aminhanifm]

What changed

• Update the README demo link to the nested portfolio URL.
• Add canonical and social metadata for the nested URL.
• Replace the old project Pages deployment with a redirect that preserves query strings and URL fragments.

Why

CSV Health now lives at https://aminhanifm.github.io/projects/csv-health/. The legacy /CSV-Health/ URL should continue guiding existing visitors and bookmarks to the new location.

Validation

• Formatting
• ESLint
• TypeScript
• 23 unit and integration tests
• Production build using --base=/projects/csv-health/
• Confirmed the nested live URL returns HTTP 200