fix(tests): strip ANSI escapes before --lang substring assertion

Rich on narrow Windows columns splits `--lang` across colour-cycle ANSI
escapes (`\x1b[..m-\x1b[..m-lang`), so the literal substring check fails
on CI even though the rendered help renders correctly for humans. CI was
red on every commit landing after #234 hit a runner with that exact
column width + Python 3.9 + Rich combination.

Mirrors the `_ANSI_RE` strip pattern in tests/test_auto_tuning.py — flat
regex over the captured output before the `in` check.

tests/test_brain_rot_multilingual.py

@@ -11,6 +11,7 @@ from __future__ import annotations
 
 import dataclasses
 import json
+import re
 from pathlib import Path
 from types import MappingProxyType
 
@@ -20,6 +21,12 @@ from typer.testing import CliRunner
 from soup_cli.cli import app
 from soup_cli.utils import brain_rot, brain_rot_lang
 
+# Strip Rich's ANSI escape sequences before substring assertions — on narrow
+# Windows columns Rich can split a flag across colour-cycle escapes
+# (e.g. `\x1b[..m-\x1b[..m-lang`), so the literal `--lang` substring fails on
+# CI even though the rendered help looks correct. Mirrors tests/test_auto_tuning.py.
+_ANSI_RE = re.compile(r"\x1b\[[0-9;]*m")
+
 
 def _write(path: Path, text: str) -> Path:
     path.write_text(text, encoding="utf-8")
@@ -451,7 +458,7 @@ class TestBrainRotCliLang:
         runner = CliRunner()
         result = runner.invoke(app, ["data", "brain-rot", "--help"])
         assert result.exit_code == 0, result.output
-        assert "--lang" in result.output
+        assert "--lang" in _ANSI_RE.sub("", result.output)
 
     def test_lang_en_default(
         self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch