fix csv format error

backend/parser.py

@@ -212,7 +212,7 @@ def _columns_missing(normalized_fieldnames: set[str], required_columns: list[str
 	return [
 		column
 		for column in required_columns
-		if column.strip().upper() not in normalized_fieldnames
+		if _normalize_column_name(column) not in normalized_fieldnames
 	]
 
 
@@ -348,7 +348,7 @@ def _parse_single_csv(
 		if not reader.fieldnames:
 			raise CsvValidationError("CSV is missing a header row.")
 
-		normalized_fieldnames = {name.strip().upper() for name in reader.fieldnames if name}
+		normalized_fieldnames = {_normalize_column_name(name) for name in reader.fieldnames if name}
 		csv_format = _detect_csv_format(normalized_fieldnames)
 
 		tests: list[TestRecord] = []
@@ -539,6 +539,13 @@ def _normalize_value(value: str | None) -> str:
 	return " ".join(value.strip().upper().split())
 
 
+def _normalize_column_name(value: str | None) -> str:
+	if value is None:
+		return ""
+	# Accept common header variants, for example: "TC ID", "TC_ID", or "TC\u00A0ID".
+	return re.sub(r"[^A-Z0-9]+", "", value.upper())
+
+
 def _normalize_yes_no(value: str | None) -> bool:
 	return _normalize_value(value) == "YES"
 
@@ -615,15 +622,15 @@ def _row_get(row: dict[str, str], key: str) -> str | None:
 	if key in row:
 		return row.get(key)
 
-	normalized_key = key.strip().upper()
+	normalized_key = _normalize_column_name(key)
 	for existing_key, value in row.items():
-		if existing_key and existing_key.strip().upper() == normalized_key:
+		if existing_key and _normalize_column_name(existing_key) == normalized_key:
 			return value
 
-	if normalized_key == "COE PAIR":
+	if normalized_key == _normalize_column_name("COE PAIR"):
 		for alias in ("COE PAIRING", "COE_PAIRING"):
 			for existing_key, value in row.items():
-				if existing_key and existing_key.strip().upper() == alias:
+				if existing_key and _normalize_column_name(existing_key) == _normalize_column_name(alias):
 					return value
 
 	return None