v0.3.0

Block editing release for @gridigor/vue-lexical.

Highlights:

• Vue DecoratorBlockNode and BlockWithAlignableContents
• selectable horizontal rules and insertion command
• reactive useLexicalNodeSelection composable
• draggable top-level blocks with Vue slots and Teleport
• selection highlighting while focus moves outside the editor
• updated Nuxt playground with block dragging and horizontal rules
• public API parity roadmap linked from the README

Roadmap: https://github.com/gridigor/vue-lexical/blob/main/docs/ROADMAP.md