Web panel: Vue 3 + gnexus-ui-kit, auth, projects, reports, i18n ...

- Monorepo packages: @ltt/shared (types+client), @ltt/ui (AnnotationEditor,
  ScreenshotViewer, ElementContext, EnvironmentInfo), @ltt/web (panel)
- Kit assets served at /assets in dev and build (absolute font URL workaround)
- Pages: login/register, projects, public project+report pages (token=auth),
  settings with en/ru switcher
- Annotation editor: pen/arrow/rect/text, Tokyo Night palette, undo,
  fraction coordinates, vector shapes persisted via attachment PATCH

Co-Authored-By: Claude Code <noreply@anthropic.com>