Refine public Hypershell site

[X1pheR]

Summary

• align public identity with the canonical Hypershell masterbrand while keeping Spiny as the mascot
• consolidate project presentation metadata and add stable project detail routes, generated sitemap and public software structured data
• make recent activity release-first, improve filters/touch behavior and retain the accepted public dashboard launcher plus mobile glass blur
• optimize public image derivatives and add build-time provenance/security checks
• expand responsive, privacy, interaction and WCAG acceptance coverage

Validation

• ./scripts/test.sh — pass (22 Python/unit/CI/deployment contracts + 16 Playwright responsive/interaction/WCAG tests)
• BASE_URL=https://www.hypershell.eu ./scripts/test.sh — pass against deployed public site
• public HTTP/content/privacy checks — pass
• git diff --check — pass

The deployed public site already runs the accepted website build; this PR publishes the exact tested source revision.