feat(website): add local image tools

[JimmyDaddy]

Summary

• add a bilingual task-focused tool hub with nine local browser workflows across both RFC phases
• share watermark, batch ZIP, invisible trace, Recipe, robustness, and lazy C2PA infrastructure without uploading images
• add navigation, homepage, README, Pagefind, HTML/XML sitemap, build contracts, dependency audits, and browser smoke coverage

Security and performance

• production browser keys are explicitly out of scope and demo keys are never persisted
• C2PA inspection is read-only; official Wasm loads only after inspection starts
• ZIP and C2PA dependencies are dynamically imported, and production audits report zero vulnerabilities
• batch processing is limited to 20 images / 80 MB and recipient packages to 30 copies

Verification

• npm run typecheck
• npm run lint
• npm test -- --runInBand (116 tests)
• npm run prepack
• npm run check:release-notes
• npm --prefix website run build
• npm --prefix website run smoke
• npm audit --omit=dev
• npm --prefix website audit --omit=dev