Harden release readiness and packaged dashboard verification

[kevintseng]

Summary

• improve dashboard locale UX so language changes apply without reload and keep i18n keys in sync
• harden import trust boundaries, hook auto-context behavior, local file permissions, and HTTP remote-bind policy
• tighten public positioning around the local MeMesh plugin wedge and update architecture/integration docs
• add packaged dashboard browser e2e smoke and gate it in CI and npm publish workflow

Verification

• npm test -- --run
• npm run build
• npm run test:packaged
• npm run test:e2e-dashboard