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>

tools/convert_salary_excel.py

@@ -186,10 +186,12 @@ def parse_sheet(ws, sheet_label=None):
         print(f"Warning: Could not find header row in sheet '{ws.title}'. Skipping.", file=sys.stderr)
         return []
 
-    # Read headers
+    # Read headers. Wrapped header cells carry a line break ("Median\nsalary"),
+    # which would survive into the category name and keep the column from
+    # pairing with its count, so collapse every whitespace run to one space.
     headers = []
     for cell in ws[header_row]:
-        headers.append(str(cell.value).strip() if cell.value else "")
+        headers.append(" ".join(str(cell.value).split()) if cell.value else "")
 
     # Find company and city columns
     company_col = None