fix(convert_salary_excel): pair count/index columns by category name, not adjacency (#219)

The sequential scan assumed count/index pairs are always adjacent.
Interleaved columns like Count_A, Count_B, Index_A, Index_B produced
wrong pairings (Count_B ↔ Index_A), silently corrupting data.

Now columns are grouped by type, then matched by the category name
derived from stripping type words. Unmatched columns fall back to
standalone value columns using the original header name.

tools/convert_salary_excel.py

@@ -132,53 +132,55 @@ def parse_sheet(ws, sheet_label=None):
             continue
         data_cols.append((i, h))
 
-    # Try to detect paired count/index columns per category
-    # Heuristic: if columns come in pairs and alternate count/index, group them
-    categories = []
-    i = 0
-    while i < len(data_cols):
-        col_idx, col_header = data_cols[i]
+    # Group data columns by detected type and derive category names
+    count_cols = []
+    index_cols = []
+    untyped_cols = []
+
+    for col_idx, col_header in data_cols:
         col_type = detect_column_type(col_header)
+        if col_type == "count":
+            cat_name = strip_type_patterns(col_header, COUNT_PATTERNS)
+            count_cols.append((col_idx, col_header, cat_name))
+        elif col_type == "index":
+            cat_name = strip_type_patterns(col_header, INDEX_PATTERNS)
+            index_cols.append((col_idx, col_header, cat_name))
+        else:
+            untyped_cols.append((col_idx, col_header))
 
-        if i + 1 < len(data_cols):
-            next_col_idx, next_col_header = data_cols[i + 1]
-            next_col_type = detect_column_type(next_col_header)
+    # Pair count/index columns by matching category name
+    categories = []
+    used_counts = set()
+    used_indexes = set()
 
-            # If we have a count/index pair, group them
-            if col_type == "count" and next_col_type == "index":
-                # Use the header minus the count/index suffix as category name
-                cat_name = strip_type_patterns(col_header, COUNT_PATTERNS)
-                if not cat_name:
-                    cat_name = f"category_{len(categories)+1}"
-                else:
-                    cat_name = cat_name.replace(" ", "_").replace("-", "_")
+    for ci, (c_idx, c_header, c_cat) in enumerate(count_cols):
+        for ii, (i_idx, i_header, i_cat) in enumerate(index_cols):
+            if ii in used_indexes:
+                continue
+            if c_cat and i_cat and c_cat == i_cat:
+                cat_name = c_cat.replace(" ", "_").replace("-", "_")
                 categories.append({
                     "name": cat_name,
-                    "count_col": col_idx,
-                    "index_col": next_col_idx,
+                    "count_col": c_idx,
+                    "index_col": i_idx,
                 })
-                i += 2
-                continue
-            elif col_type == "index" and next_col_type == "count":
-                cat_name = strip_type_patterns(col_header, INDEX_PATTERNS)
-                if not cat_name:
-                    cat_name = f"category_{len(categories)+1}"
-                else:
-                    cat_name = cat_name.replace(" ", "_").replace("-", "_")
-                categories.append({
-                    "name": cat_name,
-                    "index_col": col_idx,
-                    "count_col": next_col_idx,
-                })
-                i += 2
-                continue
+                used_counts.add(ci)
+                used_indexes.add(ii)
+                break
 
-        # Single column - treat as a standalone value
-        categories.append({
-            "name": col_header.lower().replace(" ", "_"),
-            "value_col": col_idx,
-        })
-        i += 1
+    # Remaining unmatched count columns become standalone (use original header)
+    for ci, (c_idx, c_header, _) in enumerate(count_cols):
+        if ci not in used_counts:
+            categories.append({"name": c_header.lower().replace(" ", "_"), "value_col": c_idx})
+
+    # Remaining unmatched index columns become standalone (use original header)
+    for ii, (i_idx, i_header, _) in enumerate(index_cols):
+        if ii not in used_indexes:
+            categories.append({"name": i_header.lower().replace(" ", "_"), "value_col": i_idx})
+
+    # Untyped columns become standalone
+    for col_idx, col_header in untyped_cols:
+        categories.append({"name": col_header.lower().replace(" ", "_"), "value_col": col_idx})
 
     # Parse data rows
     companies = []