feat: add Qwen Code support to Spec Kit

Add comprehensive Qwen Code integration following existing patterns:

- Add Qwen as fourth AI assistant option in CLI
- Update all documentation to include Qwen CLI references
- Extend GitHub Actions workflow for Qwen template generation
- Add Qwen support to shell scripts and templates
- Maintain backward compatibility with existing assistants

README.md

@@ -110,7 +110,7 @@ Our research and experimentation focus on:
 ## 🔧 Prerequisites
 
 - **Linux/macOS** (or WSL2 on Windows)
-- AI coding agent: [Claude Code](https://www.anthropic.com/claude-code), [GitHub Copilot](https://code.visualstudio.com/), or [Gemini CLI](https://github.com/google-gemini/gemini-cli)
+- AI coding agent: [Claude Code](https://www.anthropic.com/claude-code), [GitHub Copilot](https://code.visualstudio.com/), [Gemini CLI](https://github.com/google-gemini/gemini-cli), or [Qwen CLI](https://github.com/QwenLM/qwen-code)
 - [uv](https://docs.astral.sh/uv/) for package management
 - [Python 3.11+](https://www.python.org/downloads/)
 - [Git](https://git-scm.com/downloads)
@@ -147,11 +147,12 @@ You will be prompted to select the AI agent you are using. You can also proactiv
 specify init <project_name> --ai claude
 specify init <project_name> --ai gemini
 specify init <project_name> --ai copilot
+specify init <project_name> --ai qwen
 # Or in current directory:
 specify init --here --ai claude
 ```
 
-The CLI will check if you have Claude Code or Gemini CLI installed. If you do not, or you prefer to get the templates without checking for the right tools, use `--ignore-agent-tools` with your command:
+The CLI will check if you have Claude Code, Gemini CLI, or Qwen CLI installed. If you do not, or you prefer to get the templates without checking for the right tools, use `--ignore-agent-tools` with your command:
 
 ```bash
 specify init <project_name> --ai claude --ignore-agent-tools