fix: stop panel description churn

tests/test_text_sanitizer.py

@@ -3,7 +3,13 @@ from pathlib import Path
 
 sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "backend"))
 
-from bot.utils.text_sanitizer import sanitize_display_name, sanitize_username, username_for_display
+from bot.utils.text_sanitizer import (
+    looks_like_broken_panel_text,
+    panel_description_from_profile,
+    sanitize_display_name,
+    sanitize_username,
+    username_for_display,
+)
 
 
 def test_sanitize_username_preserves_underscore_suffixes():
@@ -22,3 +28,21 @@ def test_sanitize_username_rejects_free_form_values_instead_of_truncating():
 
 def test_display_name_filters_still_apply_to_free_form_names():
     assert sanitize_display_name("Name service") == "Name"
+
+
+def test_panel_broken_text_detection_is_conservative_about_question_marks():
+    assert not looks_like_broken_panel_text("?")
+    assert not looks_like_broken_panel_text("alice??")
+    assert not looks_like_broken_panel_text("??? 123")
+    assert not looks_like_broken_panel_text("\U0001f0cf")
+
+
+def test_panel_broken_text_detection_filters_replacement_garbage():
+    assert looks_like_broken_panel_text("????")
+    assert looks_like_broken_panel_text("???!")
+    assert looks_like_broken_panel_text("\ufffd\ufffd")
+
+
+def test_panel_description_filters_only_broken_lines():
+    assert panel_description_from_profile("alice??", "????", "Smith") == "alice??\nSmith"
+    assert panel_description_from_profile(None, "????", "\ufffd\ufffd") == ""