added cli

tests/cli/test_tree.py

@@ -0,0 +1,24 @@
+from docforge.cli.main import cli
+
+
+def test_tree_command(cli_runner, temp_package):
+    (temp_package / "mod.py").write_text(
+        '''
+class A:
+    def f(self): ...
+'''
+    )
+
+    result = cli_runner.invoke(
+        cli,
+        [
+            "tree",
+            "--modules",
+            "testpkg.mod",
+        ],
+    )
+
+    assert result.exit_code == 0
+    assert "testpkg" in result.output
+    assert "mod" in result.output
+    assert "A" in result.output