Pin text I/O to UTF-8 and fail CI on locale-dependent reads/writes (#3296)

Co-authored-by: ShuQingDollarVoyager <57471784+ShuQingDollarVoyager@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

examples/clients/simple-chatbot/mcp_simple_chatbot/main.py

@@ -44,7 +44,7 @@ class Configuration:
             FileNotFoundError: If configuration file doesn't exist.
             JSONDecodeError: If configuration file is invalid JSON.
         """
-        with open(file_path, "r") as f:
+        with open(file_path, encoding="utf-8") as f:
             return json.load(f)
 
     @property

examples/stories/_harness.py

@@ -123,7 +123,7 @@ async def _self_hosted(name: str, cfg: dict[str, Any]) -> AsyncIterator[str]:
 
 def _story_cfg(name: str) -> dict[str, Any]:
     """The manifest entry for the story ``name`` with ``[defaults]`` applied."""
-    manifest: dict[str, Any] = tomllib.loads((Path(__file__).parent / "manifest.toml").read_text())
+    manifest: dict[str, Any] = tomllib.loads((Path(__file__).parent / "manifest.toml").read_text(encoding="utf-8"))
     return manifest["defaults"] | manifest["story"].get(name, {})