docs: finalize professional README

[CoderDeltaLAN]

Finalizes the public README for the published CDLAN Portfolio.

Scope:

• replace provisional bootstrap README with a complete professional README;
• add live site, badges, publication status and project overview;
• add curated screenshots from the published portfolio;
• document quality gates, SEO/security metadata, accessibility baseline and structural verification;
• document public/private boundary, maintainer workflow, license and project status.

Constraints:

• no index.html changes;
• no backend;
• no secrets;
• no PayPal or donation section;
• no generated/vendor artifacts.

Local validation:

• scripts/verify.sh OK;
• git diff --check OK;
• screenshot references checked;
• README noise scan OK;
• pre-push validation OK.