Refactor inventory forms to include unit and location options; update quantity input handling

frontend/app/inventory/InventoryConsumeForm.tsx

@@ -38,10 +38,12 @@ export default function InventoryConsumeForm({ id, unit }: Props) {
         onSubmit={(e) => {
           e.preventDefault();
           setError(null);
-
           const form = e.currentTarget;
           const formData = new FormData(form);
-
+          const raw = formData.get('amountUsed') as string;
+          const { quantity, unit: parsedUnit } = parseQuantityInput(raw, unit);
+          formData.set('amountUsed', String(quantity));
+          formData.set('unit', parsedUnit);
           startTransition(async () => {
             try {
               await consumeInventoryItem(formData);
@@ -67,9 +69,7 @@ export default function InventoryConsumeForm({ id, unit }: Props) {
           <br />
           <input
             name="amountUsed"
-            type="number"
-            step="0.01"
-            min="0.01"
+            type="text"
             required
             style={{ width: '100%', padding: '0.5rem' }}
           />
@@ -109,4 +109,15 @@ export default function InventoryConsumeForm({ id, unit }: Props) {
       {error ? <p style={{ color: 'crimson', margin: 0 }}>{error}</p> : null}
     </div>
   );
+}
+
+function parseQuantityInput(input: string, defaultUnit: string) {
+  const match = input.trim().match(/^([\d.,]+)\s*([a-zA-Z]*)$/);
+  if (!match) return { quantity: NaN, unit: defaultUnit };
+  let [, num, unit] = match;
+  num = num.replace(',', '.');
+  unit = unit || defaultUnit;
+  if (defaultUnit === 'kg' && (unit === 'g' || unit === 'gram')) return { quantity: parseFloat(num) / 1000, unit: 'kg' };
+  if (defaultUnit === 'g' && (unit === 'kg' || unit === 'kilogram')) return { quantity: parseFloat(num) * 1000, unit: 'g' };
+  return { quantity: parseFloat(num), unit };
 }