fix(userscript): harden Shadow DOM init with lazy body wait and null guards

refactor(userscript): migrate all UI into Shadow DOM for style isolation

docs: update extension screenshots

fix: sync npm lockfile with wrangler upgrade

chore: update images cs1.png and cs2.png

feat: add Add Account button and embed Node.js server

chore: release v0.4.1

fix: optimize theme UI

fix: submitting partially forgotten code

feat(userscript): add dual theme system and refactor UI layout

fix: PBKDF2

feat: fix database_id

chore: release v0.3.1

fix: handle worker startup errors gracefully

feat: update github svg