refactor: replace AngularJS toast with vanilla HTML in Electron shell}
- Remove AngularJS dependencies (angular, angular-material, angular-animate, angular-aria, angular-messages) from package.json and Electron shell - Delete angular.mjs bootstrap and angular/toast/index.mjs factory - Add new vanilla ui.mjs with CSS-animated toast (click-to-dismiss, auto- dismiss after 5s, slide-in/out animations) - Add #p3xre-toast-container to index.html, replace AngularJS toast styles with new .p3xre-toast CSS including keyframe animations - Remove angular-csp.css and angular-material.css stylesheet links from index.html - Move p3x-action IPC handler after ui.mjs import in onload.mjs to ensure toast is initialized before use - Update README.md: replace "deferred rendering" with "CDK virtual scrolling", document ESM backend migration, dayjs, and add communication flow diagram - Remove outdated donated-ware section and AngularJS security reference from README.md - Bump p3x-redis-ui-material to ^2026.4.213 and axios to ^1.14.0 - Add changelog entry for v2026.4.202 - Delete AGENTS.md - Update yarn.lock with resolved dependency changes