so many changes

Чипы и Vue-тосты приведены к дизайну и поведению ванильной версии ...

- _chips.scss: bordered pill chips, uppercase, selectable/pressed state, success/warning/danger variants, disabled state
- demo/partials/chips.html: .chip-group wrappers, aria-pressed на selectable chips
- GnToastProvider.js: hover pause/resume, alone=true по умолчанию, CSS-анимация прогресса, close-кнопка без задержки
- Заменён avatar-placeholder.png на .jpg, используемый в демо

Add GnAvatarStack, GnChipGroup, GnCombobox and GnSearchField Vue components ...

- Mirror reference gnexus-ui-kit API for avatar stack, chip group, combobox and search field.

- Add supporting styles for .avatar-stack, .avatar-xs and .chip-group.

- Add Vue demo mounts to avatar, chips, advanced-select and inputs partials.

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

Add Tabs, Avatar, Chip, and Progress components ...

- Implement pill/compact/vertical tabs with browser helper and Vue adapters
  (GnTabs, GnTab, GnTabPanel) plus keyboard navigation.
- Add Avatar styles and GnAvatar with initials/image/icon and status dot.
- Add Chip styles and GnChip removable/selectable chip.
- Add Progress styles, browser helper, and GnProgress linear/step.
- Wire new components into kit.scss, Vue plugin, Vue entry, and browser bundle.
- Add demo partials and update docs/component-coverage.md + PROJECT_NOTES.md.
- All builds and smoke tests pass.