Fix/docs toc overflow

[66HEX]

Description

Fixes the documentation table of contents on pages with many headings, such as changelogs.

The TOC is now sticky and scrolls within the available viewport space, using the same fade mask as the command palette. Document action links remain fixed below it and no longer overlap the heading list.

The command palette footer also uses the more appropriate Hugeicons CornerDownLeftIcon next to “Go to page”.

Fixes #___

Type of Change

• New component (please include component.json and demo)
• Bug fix (non-breaking change which fixes an issue)
• Documentation update
• Refactor / Performance improvement
• CLI change

How Has This Been Tested?

The modified Svelte components were checked with the Svelte autofixer and project type checking. ESLint and Prettier also ran successfully on the staged files through the pre-commit hooks.

• Component tested in apps/docs (Playground)
• CLI tested manually with init / add
• Unit tests added/updated (if applicable)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have run pnpm run lint, pnpm run check and pnpm run format before committing
• New and existing unit tests pass locally with my changes