Add ReleaseRun HTTP Security Headers Analyzer to Security section

[Matheus-RR]

What this PR adds

Adds ReleaseRun HTTP Security Headers Analyzer to the Security section.

What it does: Free browser tool — paste your HTTP response headers (from curl -I https://your-site.com or browser DevTools) and get an instant A-F security grade.

Checks 10 security headers:

• Strict-Transport-Security (HSTS) — max-age, includeSubDomains
• Content-Security-Policy — presence of unsafe-inline/eval, wildcard sources
• X-Frame-Options — DENY/SAMEORIGIN clickjacking protection
• X-Content-Type-Options — nosniff
• Referrer-Policy — strict-origin-when-cross-origin
• Permissions-Policy — camera, microphone, geolocation
• X-XSS-Protection — legacy filter handling
• Cache-Control — no-store for sensitive pages
• Server / X-Powered-By — info leakage detection

Outputs: A-F grade (100pts), per-header PASS/WARN/FAIL with explanation, and a Nginx config snippet for any missing headers.

Free, client-side only, no signup required.

[Matheus-RR]

Closing — duplicate submission. We already have an open PR (#628) to this repo. Keeping the more recent one.