[makhnatkin]

Require a dependency set compatible with UIkit 8

• Required UIkit 8, components 5, and React/React DOM 18 or 19.
• Required editor 16 for the header, LaTeX, and Page Constructor extensions; added a workspace editor dependency for LaTeX development.
• Added explicit drag-and-drop, virtualization, and sizing dependencies for legacy components and the code language selector.
• Updated dependency catalogs and lockfile resolutions, including transitive dependencies and native-package platform metadata.

Preserve existing menus and selection behavior

• Moved menus, dropdowns, suggestion lists, and their types to the UIkit legacy entry point across the editor and demo.
• Updated menu and command/emoji suggestion styles to the legacy CSS prefixes.
• Migrated toolbar, code language, and deprecated tooltip selector option types; updated toolbar option label rendering.
• Enabled explicit virtualization for code language lists with at least 50 options.

Replace APIs removed in UIkit 8

• Updated application providers in Storybook, Playwright, and upload-hint tests.
• Migrated popup anchors and close callbacks while preserving outside-click handling in deprecated tooltip controls.
• Replaced removed spacing, gap, centering, and numeric sizing props in settings, search, table controls, and demo layouts.
• Updated the dark-theme iframe background to the contrast color token.

Keep attachment forms and prompt submission working

• Replaced legacy tabs in file and image forms with the current tab components.
• Migrated file, image, image-settings, and GPT prompt inputs to keydown handling; prevented Enter submission during input composition.
• Added form tests for tab switching, unavailable uploads, and Enter submission after composition; standardized upload-hint test names.

Retain Page Constructor support

• Required Page Constructor 9, its Diplodoc extension 0.14, and Node.js 24 or later; updated the shared Diplodoc transform target to 4.78.12.
• Migrated editing controls to the new layout, popup, and button event APIs while preserving double-click isolation.
• Added light/dark tests for content editing, autosave, Markdown/WYSIWYG switching, split preview, contrast button themes, and runtime errors.

Make the migration reviewable

• Added guidance for dependency, provider, select, and CSS migration, including compatible-release publication and lockfile refresh prerequisites.
• Updated light/dark visual baselines for settings, Mermaid, and Page Constructor.

[gravity-ui]

[gravity-ui]