fix: decode shell skill output as UTF-8

Author: VectorPeak

src/google/adk/tools/skill_toolset.py

@@ -745,6 +745,7 @@ def _build_wrapper_code(
           "        _r = subprocess.run(",
           f"          {arr!r},",
           "          capture_output=True, text=True,",
+          "          encoding='utf-8', errors='replace',",
           f"          timeout={timeout!r}, cwd=td,",
           "        )",
           "        print(_json.dumps({",

tests/unittests/tools/test_skill_toolset.py

@@ -996,6 +996,8 @@ async def test_execute_script_shell_success(mock_skill1):
   code_input = call_args[0][1]
   assert "subprocess.run" in code_input.code
   assert "bash" in code_input.code
+  assert "encoding='utf-8'" in code_input.code
+  assert "errors='replace'" in code_input.code
   assert "__shell_result__" in code_input.code