feat: add remaining reference Vue components, card variants, toolbar/repeater/activity-log/usage-meter styles and demo mounts ...

- Add GnHorizontalCard, GnUserCard, GnMetricCard, GnStatusCard, GnLoginCard,
  GnIdentity, GnActivityLog, GnToolbar, GnRouterTabs, GnRepeater, GnUsageMeter
- Extend GnTabs to support reference items API while keeping child mode
- Add card subcomponent styles: status, metric, horizontal, login, user
- Add toolbar, repeater, identity, activity-log, usage-meter styles
- Add typography token variables used by reference-compatible components
- Add Vue demo mounts for cards, data-patterns, progress, tabs, navigation-shell
- Fix GnAvatar online status class and navigation-shell footer slot
- Update screenshot config to cover skeleton and navigation-shell

Verified: npm run build, npm run test:e2e (19 passed), npm run screenshots,
npm run test:vue-adapter, figma-match (7 passed)

Polish triggers, breadcrumbs, drawer, file preview, editable icons, logos ...

- Use btn-sm for popover, tooltip, dropdown, modal-open, confirm, toast, drawer triggers.
- Use btn-md with gap for modal and confirm-popup action buttons.
- Fix left drawer: correct SCSS nesting so .drawer-left panel slides from left.
- Align breadcrumbs demo with Figma: dark surface, active pill, collapsed rows.
- Unify File Upload preview cards with static File attachment cards markup.
- Style Editable String buttons as btn-icon-only btn-sm.
- Fix 'essentials/search' icon mapping to 'essentials/zoom/search'.
- Add Logos component block from Figma frames.
- Expand screenshot section list to cover more component demos.
- All 19 e2e tests green.

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

fix: close high-severity compatibility gaps from functional audit ...

- Add missing Drawer browser helper (src/js/components/drawer.js) and export it.
- Replace icon-only Helper with full gnexus-ui-kit-compatible Helper object
  (template, unification, states).
- Make Toasts create* methods synchronous to match the reference contract.
- Rename Vue plugin export to GnexusUiVue while keeping VMKUiVue alias;
  add tryUseRouter, tryUseRoute, isRouteActive composables.
- Emit both vmk-ui-kit.* and gnexus-ui-kit.* browser bundles; point package.json
  main/module/exports to gnexus-ui-kit aliases.
- Add demo partials for GnInputGroup, GnDescriptionList, GnEmptyState, GnPageHeader.
- Update modal/drawer/toast demos to exercise the browser JS API.
- Update functional tests for dynamic modal/drawer creation.

All e2e tests pass; demo page has no console errors with the new background wrapper.

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

Add overlay components: Modal, Drawer, Toast system ...

- Add SCSS for modals, drawers and toasts with VMK design tokens.
- Add GnModal and GnDrawer Vue adapters with focus trap, Escape close and teleport.
- Add browser Toasts helper and GnToastProvider + useToast composable.
- Wire overlays into plugin, Vue entry and browser bundle.
- Add demo partials for Modal, Drawer and Toast.
- Update component coverage and project notes.