Seo fixes

[MatiasOS]

Description

Adds structured data and SEO improvements to index.html to increase visibility in rich search results and AI citations. These changes help search engines and AI systems recognize OpenScan as a blockchain explorer, differentiating it from openscan.eu (3D scanner).

Related Issue

Closes #212
Closes #213

Type of Change

• Bug fix
• New feature
• Documentation update
• Refactoring
• Performance improvement
• Other (please describe):

Changes Made

• Organization schema (JSON-LD): Added standalone Organization structured data with knowsAbout, logo, and sameAs fields for AI entity recognition and disambiguation
• WebApplication schema updates: Changed canonical URL from openscan.io to openscan.eth.link, linked sourceOrganization to the new Organization via @id
• Expanded FAQPage schema: Added 4 new questions (10 total): blockchain explorer definition, IPFS/self-hosting, ENS domain lookups, and open-source identity
• H1 heading: Added a visually-hidden H1 with descriptive keywords (OpenScan - Trustless Open-Source Blockchain Explorer) available in static HTML before JS renders
• Noscript H1 update: Updated noscript heading text to match

Screenshots (if applicable)

N/A — no visual changes. All additions are in structured data and visually-hidden elements.

Checklist

• I have run npm run format:fix and npm run lint:fix
• I have run npm run typecheck with no errors
• I have run tests with npm run test:run
• I have tested my changes locally
• I have updated documentation if needed
• My code follows the project's architecture patterns

Additional Notes

• Structured data validated with https://search.google.com/test/rich-results
• The @id with #organization is a JSON-LD convention — it's not meant to be a real navigable URL. It acts as an internal identifier so the WebApplication's sourceOrganization can reference the Organization schema on the same page, linking them together as connected data.

[github-actions]

🚀 Preview: https://pr-223--openscan.netlify.app
📝 Commit: 3dc4a84e057df18ef0fe23ba2cc184a71af8a73a