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>

Add Divider, Accordion, Stepper and FileAttachment components ...

- Implement CSS for divider, accordion, stepper and file-upload/attachment.
- Add browser Accordion helper and expose it on window.VMKUIKit.
- Add Vue adapters: GnAccordion, GnSteps, GnFileUpload, GnFileAttachment.
- Add demo partials and figma match pages for divider and attached-file.
- Fix Figma comparison flattening for transparent baselines (e.g. breadcrumbs, attached-file).
- Add vertical spacing to the demo index page to separate sections.

All Figma visual tests and the Vue adapter smoke build pass.