feat(core): add bubble menu, smart paste, outline, block drag, export, and CRDT collaboration

[Mrshiju]

Summary

Introduces high-end editing capabilities to Nexus-Editor, including a floating Bubble Menu, smart HTML-to-Markdown paste, an interactive Outline (TOC) sidebar, Notion-style block drag & reorder, multi-format export (standalone HTML, Word .doc, PDF print), and a new Yjs-based CRDT real-time collaboration plugin.

Motivation

To bridge the gap between raw Markdown editing and modern, Notion/Obsidian-grade editing workflows:

• Lower the cognitive barrier of remembering Markdown syntax via floating rich-text actions.

• Eliminate messy HTML artifacts when copying content from web pages, Word, or Excel.

• Provide document structural awareness and drag-and-drop block reordering.

• Enable multi-user collaborative editing with presence awareness and scoped undo/redo.

• Expand document export capabilities to styled HTML, Microsoft Word, and print-to-PDF.

• Issue:

• Roadmap (docs/ROADMAP.md): Phase 1 & 2 Editing Experience & Collaboration

• OpenSpec change:

Changes

packages/core

• Smart HTML Paste (src/html-to-markdown.ts): Built a zero-dependency DOM-based converter that automatically cleans and converts pasted text/html into clean GFM Markdown (including headings, nested lists, code blocks, and tables). Configurable via EditorConfig.smartPaste.
• Document Outline (TOC) Sidebar (src/outline-ui.ts): Implemented createOutlineUI providing a hierarchical heading tree, live reading cursor highlight tracking, and smooth scroll-to-heading navigation.
• Notion-Style Block Drag (src/block-drag.ts): Added blockDragExtension with block boundary detection (paragraphs, headings, code blocks, tables, lists), hoverable ⋮⋮ handle, custom ghost-free mouse drag, and atomic transaction-based block swapping.
• Multi-Format Export Suite (src/export.ts): Added exportStandaloneHTML (with GitHub-like typography and print styles), exportWord (Word/WPS-compatible XML document format), and print (browser/Electron native PDF print dialog trigger).
• Core Engine Optimizations (src/editor.ts, src/types.ts): Added onAstChange callback to decouple high-frequency text events from AST processing; wired export APIs into EditorAPI.

packages/plugin-toolbar

• Floating Bubble Menu (src/bubble-menu.ts): Implemented createBubbleMenuUI which automatically calculates bounding coordinates and floats above non-empty selections, supporting bold, italic, strikethrough, underline, inline code, link, headings (H2/H3), and text/highlight color pickers.
• Dropdown & Palette Exports (src/toolbar-ui.ts): Exported showColorPicker, pickOverlayMount, and default color palettes for shared use.

packages/plugin-collab (NEW PACKAGE)

• CRDT Real-Time Collaboration: Created a standalone @floatboat/nexus-plugin-collab package using yjs, y-codemirror.next, and y-protocols/awareness.
• Remote Presence & Cursors: Renders remote cursors, active selections, and colored username tags.
• Collaborative Undo: Scoped via Y.UndoManager so Ctrl+Z only reverts local changes without reverting other peers' edits.
• Local Synchronization: Provided linkDocs for memory linking and LocalBroadcastProvider for zero-server multi-tab/window sync via BroadcastChannel.

packages/plugin-history

• History Grouping Window: Increased default newGroupDelay from 500ms to 1500ms to group consecutive typing into natural pause intervals; exposed HistoryPluginOptions.

packages/plugin-search

• Fuzzy Search: Implemented a lightweight inline fuzzyMatch algorithm with run-length continuity scoring, supporting SearchOptions.fuzzy in findSearchMatches.

apps/electron-demo & Workspace

• Vite Resolve Aliases: Resolved missing aliases for @floatboat/nexus-plugin-math and @floatboat/nexus-plugin-vim.
• Tooling: Registered @floatboat/nexus-plugin-collab in vitest.config.ts and root package.json build scripts; excluded .kilo from Vitest discovery.

Testing

• pnpm test passes / All 25 test suites and 391 unit tests pass (100% green).
• Affected packages build (pnpm build) passes cleanly.
• New / updated vitest cases:
  • packages/core/test/html-to-markdown.test.ts: HTML element conversions, table formatting, editor smart paste.
  • packages/core/test/outline-ui.test.ts: TOC hierarchy, document change syncing, selection jumping.
  • packages/core/test/block-drag.test.ts: Block boundary detection, handle & indicator initialization.
  • packages/core/test/export.test.ts: Standalone HTML generation, Word document structure, print invocation.
  • packages/plugin-toolbar/test/plugin-toolbar.test.ts: Bubble menu mounting, button rendering, selection actions.
  • packages/plugin-collab/test/plugin-collab.test.ts: Yjs two-way sync, multi-client doc linking, awareness presence, collaborative undo.
  • packages/plugin-search/test/plugin-search.test.ts: Inline fuzzy match scoring and ranked match retrieval.
  • packages/core/test/editor.test.ts: Added onAstChange independent callback test.
• Manual UI check in electron-demo: Verified Vite dev server startup without package resolution errors.

Compliance

• CLA signed
• New dependencies:
  • yjs@^13.6.24 — MIT — CRDT core store for real-time collaboration.
  • y-codemirror.next@^0.3.5 — MIT — Official CodeMirror 6 binding for Yjs.
  • y-protocols@^1.0.6 — MIT — Awareness and presence protocol.
• No build artifacts committed.
• No secrets / .env / personal vault data committed.

Checklist

• Title follows Conventional Commits.
• Public API changes update package types and interfaces.
• Did not violate the 12 Table Widget rules in live-preview-table.ts.
• Change aligns with project scope (GOVERNANCE.md §4).

[CLAassistant]

All committers have signed the CLA.