feat: complete code cleanup and create feature parity plan

Major Architecture Improvements:
- Separate JavaScript library (lib/) with proper build system
- Go CLI with embedded library using go:embed
- Hot reload development with Air integration
- Library + CLI build pipeline with npm run build

Code Cleanup:
- Remove obsolete assets (insertr-cli/assets/editor/)
- Clean up package.json metadata and dependencies
- Update .gitignore for new architecture
- Remove unused 'marked' dependency

New Documentation:
- Add comprehensive TODO.md with feature gap analysis
- Document critical gaps between prototype and current library
- Create phased implementation plan for feature parity
- Update DEVELOPMENT.md with hot reload workflow
- Add LIBRARY.md documenting new architecture

Hot Reload System:
- Air watches both Go CLI and JavaScript library
- Library changes trigger: rebuild → copy → CLI rebuild → serve
- Seamless development experience across full stack

Next Steps:
- Current library is basic proof-of-concept (prompt() editing)
- Archived prototype has production-ready features
- Phase 1 focuses on professional forms and authentication
- Phase 2 adds validation and content persistence

DEVELOPMENT.md

@@ -2,30 +2,52 @@
 
 ## Quick Start
 
+### Full-Stack Development (Recommended)
 1. **Install dependencies**:
    ```bash
-   npm install
+   npm install                    # Root project dependencies
+   cd lib && npm install         # Library dependencies
    ```
 
-2. **Start development server**:
+2. **Start hot reload development**:
    ```bash
-   npm run dev
+   cd insertr-cli && air         # Starts server with library hot reload
    ```
-   This will start live-server on http://localhost:3000 and automatically open the demo site.
+   - Watches both Go CLI changes AND JavaScript library changes
+   - Automatically rebuilds library → CLI → serves enhanced content
+   - Visit http://localhost:3000 to see results
 
-3. **Alternative commands**:
-   ```bash
-   npm run dev:about    # Open about page directly
-   npm run serve        # Alias for npm run dev
-   ```
+### Library-Only Development
+```bash
+cd lib && npm run watch         # Just develop the JavaScript library
+```
+
+### Legacy Frontend Development
+```bash
+npm run dev                     # Legacy live-server (demo-site only)
+```
 
 ## Development Workflow
 
-### Frontend Development (Current Phase)
+### Hot Reload Development (Current Phase)
+
+**🔥 NEW**: Full-stack hot reload with Air integration!
+
+- **Library Source**: `lib/src/` - Independent JavaScript library
+- **CLI Integration**: `insertr-cli/` - Go CLI with embedded library
+- **Demo Site**: `demo-site/` - Test website for enhancement
+- **Automatic Rebuilds**: Changes to JS library trigger full rebuild cycle
+
+#### How Hot Reload Works:
+1. Edit JavaScript in `lib/src/` 
+2. Air detects changes → Rebuilds library → Copies to CLI → Rebuilds CLI
+3. Enhanced development server serves updated content
+4. Manual browser refresh shows changes
+
+### Legacy Frontend Development
 
 - **Demo Site**: `demo-site/` contains the prototype website
-- **Core Library**: `demo-site/insertr/insertr.js` - the main Insertr library
-- **Styling**: `demo-site/insertr/insertr.css` - edit interface styles
+- **Core Library**: `demo-site/insertr/insertr.js` - the old prototype library  
 - **Mock API**: `demo-site/mock-api/content.json` - sample backend data structure
 
 ### Testing the Three User Types
@@ -36,9 +58,15 @@
 
 ### Making Changes
 
+#### Modern Development (lib/ + insertr-cli/)
+- **Library Changes**: Edit `lib/src/**/*.js` → Air automatically rebuilds everything
+- **CLI Changes**: Edit Go files in `insertr-cli/` → Air rebuilds and restarts server  
+- **Demo Content**: Edit `demo-site/*.html` → Air serves enhanced versions
+- **Hot Reload**: Changes trigger full rebuild cycle (library → CLI → enhanced content)
+
+#### Legacy Development (demo-site/)
 - **Live Reload**: The server automatically refreshes when you save changes
-- **JavaScript**: Edit `demo-site/insertr/insertr.js` to modify core functionality
-- **Styling**: Edit `demo-site/insertr/insertr.css` for UI changes
+- **JavaScript**: Edit `demo-site/insertr/insertr.js` for prototype functionality
 - **Content**: Edit HTML files to test different content structures
 
 ### Adding New Features
@@ -51,40 +79,67 @@
 
 ```
 insertr/
-├── INITIAL.md              # Project requirements and research
 ├── DEVELOPMENT.md          # This file
-├── package.json            # Node.js project configuration
-├── .gitignore             # Git ignore rules
+├── LIBRARY.md             # Library architecture documentation  
+├── package.json           # Root project configuration
 │
-├── demo-site/             # Frontend prototype
+├── lib/                   # 🆕 Independent JavaScript Library
+│   ├── src/
+│   │   ├── core/
+│   │   │   ├── insertr.js    # Core library functionality
+│   │   │   ├── editor.js     # Visual editing interface
+│   │   │   └── api-client.js # Content API client
+│   │   └── index.js          # Library entry point
+│   ├── dist/
+│   │   ├── insertr.js        # Built library (development)
+│   │   └── insertr.min.js    # Built library (production)
+│   ├── package.json          # Library dependencies
+│   └── rollup.config.js      # Build configuration
+│
+├── insertr-cli/           # 🆕 Go CLI with Embedded Library
+│   ├── pkg/content/
+│   │   ├── assets/           # Embedded library files (auto-copied)
+│   │   ├── library.go        # Go embed declarations  
+│   │   ├── enhancer.go       # HTML enhancement orchestrator
+│   │   ├── injector.go       # Content injection logic
+│   │   └── ...
+│   ├── scripts/
+│   │   └── rebuild-library.sh # Air helper script
+│   ├── .air.toml            # Hot reload configuration
+│   └── insertr             # Built CLI executable
+│
+├── demo-site/             # Test website for enhancement
 │   ├── index.html         # Demo homepage
 │   ├── about.html         # Demo about page
-│   ├── README.md          # Demo usage instructions
-│   │
-│   ├── assets/            # Demo site assets
-│   │   └── style.css      # Demo site styling
-│   │
-│   ├── insertr/           # Core Insertr library
-│   │   ├── insertr.js     # Main library file
-│   │   ├── insertr.css    # Edit interface styles
-│   │   └── components/    # Future: reusable edit components
-│   │
-│   └── mock-api/          # Backend planning
-│       └── content.json   # Sample data structure
+│   └── assets/style.css   # Demo site styling
 │
-└── backend/               # Future: Go backend
-    ├── main.go           # Future: HTTP server
-    ├── api/              # Future: REST endpoints
-    └── storage/          # Future: file-based storage
+└── scripts/
+    └── build.js           # Integrated build script
 ```
 
 ## Development Scripts
 
-- `npm run dev` - Start development server with live reload
-- `npm run dev:about` - Start server opening about page
-- `npm run build` - Future: Bundle library for distribution
-- `npm run test` - Future: Run tests
-- `npm run lint` - Future: Code linting
+### Root Scripts
+- `npm run build` - Build library + CLI with embedded assets
+- `npm run dev` - Legacy live-server (demo-site only)
+
+### Library Scripts (cd lib/)  
+- `npm run build` - Build library to dist/
+- `npm run watch` - Watch and rebuild library on changes
+
+### CLI Scripts (cd insertr-cli/)
+- `air` - 🔥 Hot reload server (library + CLI + enhanced content)
+- `go build -o insertr` - Manual CLI build
+- `./insertr enhance <dir>` - Enhance static site
+- `./insertr servedev <dir>` - Development server with enhancement
+
+### Hot Reload Workflow
+```bash
+cd insertr-cli && air    # Start hot reload development
+# Edit lib/src/**/*.js   # Air detects → rebuilds → serves
+# Edit cmd/**/*.go       # Air detects → rebuilds → serves  
+# Edit ../demo-site/     # Air serves enhanced versions
+```
 
 ## Testing Different Scenarios