Исправления по результатам повторного визуального ревью: Vue form states, cluster utility, cards label, progress/loader demo ...

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

Add Vue components and demo mounts for divider, step, chips, avatar, choices, select, textarea, pagination, loader ...

- Create GnDivider and GnStep Vue components.
- Export GnStep and GnDivider via plugin and index.
- Update GnSteps to render check icon for complete steps.
- Add Vue demo mounts to divider, stepper, select-textarea, pagination, loader, chips, avatar, choices partials.
- Convert chips and avatar partials to demo-section for screenshot capture.
- Expand screenshot section list.
- All 19 e2e tests green.

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

Add Popover, Pagination, Timeline and Loader components ...

- Add Popover CSS/browser helper/Vue adapter with click-outside and Escape handling.
- Add Pagination CSS and GnPagination Vue adapter.
- Add Timeline CSS and GnTimeline Vue adapter.
- Add Loader/Spinner CSS/browser helper/Vue adapter with spin/dots/bar variants.
- Wire all four components into the SCSS entry, browser bundle, Vue plugin and exports.
- Add demo partials for popover, pagination, timeline and loader.

E2E and Vue adapter smoke builds pass.