Polish CSV Health v1 presentation

[aminhanifm]

Summary

• Add accessible GitHub source links to the landing page and report experience.
• Make quality indicators easier to scan with totals, severity and category filters, and an accessible show-all control.
• Add generated sample-data screenshots, improved README demo presentation, social metadata, JSON-LD, and the v1.0.0 changelog.
• Extend unit, integration, and Playwright coverage for the new presentation and filtering behavior.

Why

This prepares CSV Health for public portfolio review and a v1.0.0 release while preserving the existing profiling calculations, privacy boundary, visual identity, and accessibility work.

Validation

• npm run format
• npm run lint
• npm run typecheck
• npm test with 26 passing tests
• npm run build
• npm run test:e2e with 3 passing Playwright journeys
• Desktop and 390 px mobile browser verification
• No console errors, page-level horizontal overflow, CSV network transmission, analytics, or remote scripts