fix: force UTF-8 stdout on Windows for CJK CLI output

On Windows the default Python stdout encoding follows the system
ANSI code page (cp950 for zh-TW, cp932 for ja, cp949 for ko).
`click.echo()` then raises `UnicodeEncodeError` whenever a CJK
character lands in CLI output — `jarvis ask` returning Chinese
crashes with `'cp950' codec can't encode character '义'`.

Reconfigure `sys.stdout` and `sys.stderr` to UTF-8 with
`errors='replace'` at the `main()` entry point. Scoped to
`win32` so other platforms are untouched. Two unit tests verify
the reconfigure happens on Windows and doesn't on Linux.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/openjarvis/cli/__init__.py

@@ -140,6 +140,15 @@ except ImportError:
 
 def main() -> None:
     """Entry point registered as ``jarvis`` console script."""
+    import sys
+
+    if sys.platform == "win32":
+        for _stream in (sys.stdout, sys.stderr):
+            if hasattr(_stream, "reconfigure"):
+                try:
+                    _stream.reconfigure(encoding="utf-8", errors="replace")
+                except (AttributeError, OSError):
+                    pass
     cli()
 
 

tests/cli/test_cli.py

@@ -2,13 +2,52 @@
 
 from __future__ import annotations
 
+import io
+import sys
 from pathlib import Path
 from unittest import mock
 
 from click.testing import CliRunner
 
 import openjarvis
-from openjarvis.cli import cli
+from openjarvis.cli import cli, main
+
+
+class TestMainEntryPoint:
+    """Tests for the ``jarvis`` console script entry point."""
+
+    def test_windows_reconfigures_stdout_to_utf8(self) -> None:
+        """On Windows, main() must reconfigure stdout/stderr to UTF-8 so that
+        CJK characters in CLI output don't trigger UnicodeEncodeError under
+        legacy code pages (cp950, cp932, cp949)."""
+        stdout_mock = mock.MagicMock(spec=io.TextIOWrapper)
+        stderr_mock = mock.MagicMock(spec=io.TextIOWrapper)
+        with (
+            mock.patch.object(sys, "platform", "win32"),
+            mock.patch.object(sys, "stdout", stdout_mock),
+            mock.patch.object(sys, "stderr", stderr_mock),
+            mock.patch("openjarvis.cli.cli") as cli_mock,
+        ):
+            main()
+        stdout_mock.reconfigure.assert_called_once_with(
+            encoding="utf-8", errors="replace"
+        )
+        stderr_mock.reconfigure.assert_called_once_with(
+            encoding="utf-8", errors="replace"
+        )
+        cli_mock.assert_called_once()
+
+    def test_non_windows_does_not_reconfigure(self) -> None:
+        """On non-Windows platforms, stdout/stderr are left untouched."""
+        stdout_mock = mock.MagicMock(spec=io.TextIOWrapper)
+        with (
+            mock.patch.object(sys, "platform", "linux"),
+            mock.patch.object(sys, "stdout", stdout_mock),
+            mock.patch("openjarvis.cli.cli") as cli_mock,
+        ):
+            main()
+        stdout_mock.reconfigure.assert_not_called()
+        cli_mock.assert_called_once()
 
 
 class TestCLI: