docs: expand product logo usage

[reiase]

Summary

• add the full Persisting, pVisor, and pChronicle icon and wordmark set to the Docusaurus static assets
• use the new Persisting mark for the favicon and navbar
• use product wordmarks in the README and English/Chinese product landing pages
• keep the logo assets available for future documentation surfaces

Validation

• npm run typecheck --prefix docs
• npm run build --prefix docs
• git diff --check