docs: Add Docker section to README

- Added Docker instructions for testing without local install
- Fixed clone URL to point to Gitea

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

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

README.md

@@ -36,7 +36,7 @@ A standalone PyQt6-based editor for creating visual artifacts. Designed to integ
 
 ```bash
 # Clone and install
-git clone <repo>
+git clone https://gitea.brrd.tech/rob/artifact-editor.git
 cd artifact-editor
 pip install -e .
 
@@ -50,6 +50,32 @@ sudo apt install openscad              # For 3D CAD
 pip install pygments pillow            # For code syntax highlighting
 ```
 
+## Docker
+
+Run without installing anything locally (all dependencies included):
+
+```bash
+# Clone the repo
+git clone https://gitea.brrd.tech/rob/artifact-editor.git
+cd artifact-editor
+
+# Build (automatically clones SmartTools from Gitea)
+docker-compose build
+
+# Run tests
+docker-compose run --rm test
+
+# Use the CLI tools
+docker-compose run --rm cli artifact-ai --format plantuml --instruction "Create a class diagram"
+echo "@startuml\nA->B\n@enduml" | docker-compose run --rm cli artifact-export --format plantuml --to /dev/stdout
+
+# Launch GUI (requires X11: xhost +local:docker)
+docker-compose run --rm gui
+
+# Interactive shell
+docker-compose run --rm shell
+```
+
 ## Usage
 
 ### Launch the GUI Editor