chore: clean up easy maintenance tasks

[benvinegar]

Summary

• Route package scripts through the named build:viewer script instead of raw vite build.
• Update stale mobile CSS selectors to the current native surface class names.
• Switch storage stress random fixtures to canonical json/terminal surface payload fields.

Tests

• npm run format:check
• npm run lint
• npm run typecheck
• npm test -- test/storageStress.test.ts (runs the full configured unit/API suite)
• npm run build
• npm run changeset:status -- --since=origin/main

This PR description was generated by Pi using OpenAI GPT-5