build: configure npm package for publication

Phase 4-5 Complete:
- ✅ Updated package.json to v1.0.0 with proper entry points
- ✅ Added peer dependency on marked.js (^11.0.0 || ^12.0.0 || ^13.0.0)
- ✅ Set module type to ESM to fix Rollup warnings
- ✅ Configured files array for distribution (dist/ only)
- ✅ Added prepublishOnly script (build + test)
- ✅ Created .npmignore to exclude dev files
- ✅ Created CHANGELOG.md following Keep a Changelog format

Package details:
- Main: dist/testdrive-jsui.cjs.js (CommonJS)
- Module: dist/testdrive-jsui.esm.js (ES Module)
- Browser: dist/testdrive-jsui.min.js (107KB minified)
- Style: dist/testdrive-jsui.css
- Total package size: 445.9 KB (13 files)

npm pack --dry-run verified successfully!

CHANGELOG.md

@@ -0,0 +1,63 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [1.0.0] - 2025-12-16
+
+### Added
+- Initial public release of TestDrive-JSUI as standalone npm package
+- JavaScript-first markdown editor library
+- Section-based editing with independent section management
+- Interactive UI with compass-positioned control panels
+- Support for edit and view modes
+- Event-driven API for integration
+- Auto-save functionality to localStorage
+- Keyboard shortcuts (Ctrl+S to save, Escape to cancel)
+- LocalStorage integration for content persistence
+- Download markdown as .md file
+- Table of contents generation
+- Debug panel with logging system
+- Status control showing document statistics
+- Comprehensive test suite (68 Jest tests + 15 pytest tests)
+- Full documentation (README, ARCHITECTURE, NPM_PUBLICATION_PLAN)
+
+### Features
+- **Core Library**: Pure JavaScript with marked.js as only peer dependency
+- **Bundled Distribution**: Single-file UMD, ESM, and CJS builds
+- **CSS Included**: Complete styling with GitHub theme
+- **Peer Dependency**: Uses marked.js for markdown parsing
+- **Multiple Installation Methods**: npm, CDN (jsdelivr, unpkg), direct download
+- **Source Maps**: Available for all builds for debugging
+- **Browser Support**: Modern browsers (Chrome 60+, Firefox 60+, Safari 12+, Edge 79+)
+
+### Technical
+- Built with Rollup bundler
+- Transpiled with Babel for broad browser support
+- Minified with Terser (107KB minified)
+- CSS processed with PostCSS, autoprefixer, and cssnano
+- 68 JavaScript tests passing (Jest)
+- 15 Python integration tests passing (pytest)
+
+### Package Details
+- **UMD Build**: 217KB (browser-friendly, default)
+- **Minified**: 107KB (production-ready)
+- **ESM Build**: 199KB (for modern bundlers)
+- **CJS Build**: 199KB (for Node.js)
+- **CSS**: 6KB (minified, all styles inlined)
+
+### Migration Notes
+- Fully migrated from MarkiTect monorepo to standalone capability
+- All 24 original JavaScript files consolidated
+- Single source of truth in `/capabilities/testdrive-jsui/js/`
+- Legacy files cleaned up from main application
+
+## [Unreleased]
+
+Nothing yet.
+
+---
+
+[1.0.0]: https://github.com/markitect/testdrive-jsui/releases/tag/v1.0.0