fix: update CommandRegistrar qwen config to Markdown format

extensions.py CommandRegistrar.AGENT_CONFIGS['qwen'] was still set to
TOML format, causing `specify extension` to write .toml files into
.qwen/commands, conflicting with Qwen Code CLI v0.10.0+ expectations.

- Change qwen format from toml to markdown
- Change qwen args from {{args}} to $ARGUMENTS
- Change qwen extension from .toml to .md
- Add test to assert qwen config is Markdown format

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: fuyongde

src/specify_cli/extensions.py

@@ -692,9 +692,9 @@ class CommandRegistrar:
         },
         "qwen": {
             "dir": ".qwen/commands",
-            "format": "toml",
-            "args": "{{args}}",
-            "extension": ".toml"
+            "format": "markdown",
+            "args": "$ARGUMENTS",
+            "extension": ".md"
         },
         "opencode": {
             "dir": ".opencode/command",

tests/test_extensions.py

@@ -412,6 +412,15 @@ def test_codex_agent_config_present(self):
         assert "codex" in CommandRegistrar.AGENT_CONFIGS
         assert CommandRegistrar.AGENT_CONFIGS["codex"]["dir"] == ".codex/prompts"
 
+    def test_qwen_agent_config_is_markdown(self):
+        """Qwen should use Markdown format with $ARGUMENTS (not TOML)."""
+        assert "qwen" in CommandRegistrar.AGENT_CONFIGS
+        cfg = CommandRegistrar.AGENT_CONFIGS["qwen"]
+        assert cfg["dir"] == ".qwen/commands"
+        assert cfg["format"] == "markdown"
+        assert cfg["args"] == "$ARGUMENTS"
+        assert cfg["extension"] == ".md"
+
     def test_parse_frontmatter_valid(self):
         """Test parsing valid YAML frontmatter."""
         content = """---