docs: Update README with interactive SVG editing features

- Add interactive SVG editing to features list
- Document click-to-select, drag-to-move, resize handles
- Add Delete key and visual editing shortcuts
- Update SVG section with full feature list
- Note that undo/redo works for visual changes too

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -7,12 +7,14 @@ A standalone PyQt6-based editor for creating visual artifacts. Designed to integ
 ## Features
 
 - **Split-view interface** - Code editor on the left, live preview on the right
-- **Multi-format support** - PlantUML, Mermaid, and OpenSCAD
+- **Multi-format support** - PlantUML, Mermaid, OpenSCAD, Code, SVG, and Excalidraw
+- **Interactive SVG editing** - Click to select, drag to move, resize with handles
 - **Elements panel** - View and manage diagram elements
-- **Visual editing** - Add, edit, and delete elements via dialogs
+- **Visual editing** - Add, edit, and delete elements via dialogs or directly in preview
 - **Templates** - Start from pre-built templates for common diagrams
 - **Syntax highlighting** - Format-specific code highlighting
-- **Live preview** - See changes as you type
+- **Live preview** - See changes as you type (bidirectional sync)
+- **Undo/Redo** - Works for both code and visual changes
 - **3D controls** - Rotate/pan OpenSCAD models with mouse
 
 ## Supported Artifact Types
@@ -22,6 +24,9 @@ A standalone PyQt6-based editor for creating visual artifacts. Designed to integ
 | `plantuml` | UML diagrams (class, sequence, component, etc.) | Element editing, relationships, click-to-select |
 | `mermaid` | Flowcharts, sequence, ER, state diagrams | Node editing with shapes, connections |
 | `openscad` | 3D parametric CAD models | Transform controls (translate/rotate/scale), module insertion |
+| `code` | Syntax-highlighted code snippets | 500+ languages, multiple themes, line numbers, font size |
+| `svg` | Direct SVG graphics editing | Interactive visual editing, drag/resize, UI wireframes |
+| `excalidraw` | Hand-drawn style diagrams | Sketch-like visuals, AI-readable JSON, whiteboard style |
 
 ## Installation
 
@@ -38,6 +43,7 @@ pip install PyQt6
 sudo apt install plantuml              # For PlantUML
 npm install -g @mermaid-js/mermaid-cli # For Mermaid
 sudo apt install openscad              # For 3D CAD
+pip install pygments pillow            # For code syntax highlighting
 ```
 
 ## Usage
@@ -51,6 +57,9 @@ artifact-editor
 # Launch for specific format
 artifact-editor --type mermaid
 artifact-editor --type openscad
+artifact-editor --type code
+artifact-editor --type svg
+artifact-editor --type excalidraw
 
 # Open existing file
 artifact-editor --type plantuml --initial-file diagram.puml
@@ -82,6 +91,30 @@ artifact-editor --type plantuml --initial-file diagram.puml
 - Insert at cursor, end of file, or inside modules
 - 3D preview with mouse rotation
 
+**For Code:**
+- Syntax highlighting for 500+ programming languages
+- Multiple color themes (Monokai, Dracula, GitHub, etc.)
+- Line numbers toggle
+- Adjustable font size
+- Live preview as you type
+
+**For SVG:**
+- **Interactive visual editing** - Click elements to select, drag to move, resize with corner handles
+- Direct vector graphics editing in code or visually
+- UI wireframe templates (login forms, dashboards, mobile screens)
+- Pre-built UI components (buttons, inputs, cards, modals, navbars)
+- System architecture and flowchart templates
+- Pixel-perfect element positioning using SVG renderer bounds
+- Delete key removes selected elements
+- All visual changes are undoable with Ctrl+Z
+
+**For Excalidraw:**
+- Hand-drawn/sketch-style diagrams
+- AI-readable JSON format (perfect for AI collaboration)
+- Whiteboard-style visuals that invite discussion
+- Flowcharts, mind maps, and wireframe templates
+- Exports to SVG or native .excalidraw format
+
 ## Architecture
 
 ```
@@ -97,15 +130,21 @@ artifact-editor/
 │   └── renderers/          # Convert source to visual output
 │       ├── plantuml.py
 │       ├── mermaid.py
-│       └── openscad.py
+│       ├── openscad.py
+│       ├── code.py         # Pygments-based syntax highlighting
+│       ├── svg.py          # Direct SVG editing with UI components
+│       └── excalidraw.py   # Hand-drawn style diagrams
 ```
 
 ## Keyboard Shortcuts
 
 - **Ctrl+S** - Save file
-- **Ctrl+Z** - Undo
+- **Ctrl+Z** - Undo (works for both code and visual edits)
 - **Ctrl+Y** - Redo
+- **Delete** - Remove selected element (SVG mode)
 - **Ctrl+Mouse wheel** - Zoom preview
+- **Click+Drag** - Move elements in SVG preview
+- **Corner handles** - Resize selected elements in SVG preview
 
 ## Integration