Fix: Implement dynamic column detection to handle Excel structure changes (insertion of PM Classification). This fixes the Missing data error in Pricing Units and other views.

src/contexts/ColumnsContext.tsx

@@ -0,0 +1,23 @@
+import React, { createContext, useContext, useMemo } from 'react';
+import { COLUMNS, resolveColumnIndices } from '../types';
+
+type ColumnIndices = typeof COLUMNS;
+
+const ColumnsContext = createContext<ColumnIndices>(COLUMNS);
+
+export function ColumnsProvider({ headers, children }: { headers: string[], children: React.ReactNode }) {
+  const resolved = useMemo(() => {
+    if (!headers || headers.length === 0) return COLUMNS;
+    return resolveColumnIndices(headers);
+  }, [headers]);
+
+  return (
+    <ColumnsContext.Provider value={resolved}>
+      {children}
+    </ColumnsContext.Provider>
+  );
+}
+
+export function useColumns() {
+  return useContext(ColumnsContext);
+}