fix(salary): collapse line breaks in wrapped workbook headers (#643)

* fix(salary): collapse line breaks in wrapped workbook headers

A wrapped header cell ("Median\nsalary", "Løn-\nindeks") kept its line
break, so the converter derived a category name containing a newline:
the column no longer paired with its count column, and salary_lookup
printed the category label across two lines.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(changelog): record fix for #643

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* changelog: place the #643 entry under [Unreleased]

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Mads Lorentzen <madslorentzen_17@hotmail.com>

tests/test_salary_wrapped_header_cli.py

@@ -0,0 +1,50 @@
+"""Wrapped workbook header cells must convert like their one-line spelling."""
+import json
+from pathlib import Path
+import subprocess
+import sys
+from tempfile import TemporaryDirectory
+import unittest
+
+try:
+    import openpyxl
+except ImportError:
+    openpyxl = None
+
+
+TOOL = Path(__file__).resolve().parent.parent / "tools" / "convert_salary_excel.py"
+
+
+@unittest.skipUnless(openpyxl, "requires optional openpyxl (installed in CI)")
+class WrappedHeaderCLI(unittest.TestCase):
+    def convert(self, header):
+        with TemporaryDirectory() as directory:
+            root = Path(directory)
+            workbook, output = root / "salary.xlsx", root / "salary_data.json"
+            book = openpyxl.Workbook()
+            try:
+                book.active.append(header)
+                book.active.append(["Acme", "Aarhus", 12, 104.5])
+                book.save(workbook)
+            finally:
+                book.close()
+            result = subprocess.run(
+                [sys.executable, str(TOOL), str(workbook), "--output", str(output)],
+                cwd=root, capture_output=True, text=True,
+            )
+            self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+            return json.loads(output.read_text(encoding="utf-8"))["companies"][0]["categories"]
+
+    def test_wrapped_headers_pair_like_their_single_line_spelling(self):
+        expected = {"all_employees": {"count": 12, "index": 104.5}}
+        self.assertEqual(self.convert(["Company", "City", "Employees", "Median salary"]), expected)
+        self.assertEqual(self.convert(["Company", "City", "Employees", "Median\nsalary"]), expected)
+        self.assertEqual(self.convert(["Firma", "By", "Antal\nmedarbejdere", "Løn-\nindeks"]), expected)
+
+    def test_wrapped_category_name_has_no_line_break(self):
+        categories = self.convert(["Company", "City", "Count\nengineers", "Index\nengineers"])
+        self.assertEqual(categories, {"engineers": {"count": 12, "index": 104.5}})
+
+
+if __name__ == "__main__":
+    unittest.main()