- add clipboard.js with htmlToBlocks, blocksToHtml, and blocksToPlainText helpers
- handle single-paragraph html paste as inline splice preserving block type
- handle multi-block html paste by splitting current block and merging head/tail paragraphs
- add onPasteInline and onPasteBlocks props to Block component
- implement handlePasteInline and handlePasteBlocks in BlockEditor
- fallback to plain text insertion when html is absent or yields no blocks
- update README to document clipboard behaviour and new paste handlers
- update blockRegistry to accept ReactNode icons instead of emoji strings
- replace emoji icons in all built-in block types with icon components from shared icons
- add `isHexColor` and `collectUsedColors` helpers to inline/types.js
- extend `color` and `highlight` marks to accept hex color strings in addition to palette keys
- pass `usedColors` (collected from document) to InlineToolbar
- update InlineToolbar color popover to show used colors and a free color input
- add new icons to shared icons index
- update README to reflect icon, color, and toolbar popover changes
- migrate block content from plain strings to InlineNode[] structure
- add inline toolbar (bold, italic, code, color, link) on text selection
- add checklist block type with toggle support
- add image block type (URL-based, phase 2)
- add inline serialization helpers (inlineToDom, domToInline)
- add inline types and length utilities
- extend caret utils with range get/set support
- update block registry and all existing block types for new content model
- update demo blocks in ComponentsPage to use rich inline content
- update README to reflect new architecture