feat: Implement category and unit selection for inventory items

- Added a new 'category' field to the InventoryItem entity and updated the database schema.
- Replaced free-text input for 'unit' and 'category' with select dropdowns in the AddItemModal.
- Introduced a new API endpoint to fetch metadata for units and categories.
- Updated inventory filtering logic to use the new 'category' field instead of 'consumable'.
- Enhanced validation for item creation and updates to ensure valid unit and category values.
- Updated tests to cover new functionality and ensure proper validation.

assets/admin/components/inventory/AddItemModal.tsx

@@ -1,11 +1,13 @@
 import React, { useEffect, useState } from 'react';
 import Modal from '../ui/Modal';
+import SearchableSelect from '../ui/SearchableSelect';
 import { rialToToman, tomanToRial, toEnglishDigits } from '../../lib/utils';
-import type { InventoryItem, ItemPayload } from '../../hooks/useInventory';
+import type { InventoryItem, InventoryMeta, ItemPayload } from '../../hooks/useInventory';
 
 interface Props {
   open: boolean;
   editing: InventoryItem | null;
+  meta: InventoryMeta;
   saving: boolean;
   onClose: () => void;
   onSave: (payload: ItemPayload, uuid?: string) => void;
@@ -14,20 +16,22 @@ interface Props {
 interface FormState {
   name: string;
   consumable: string;
+  category: string;
   unit: string;
   price: string;   // Toman, as typed
   stock: string;
   alertThreshold: string;
 }
 
-const BLANK: FormState = { name: '', consumable: '', unit: '', price: '', stock: '', alertThreshold: '' };
+const DEFAULT_UNIT = 'عدد';
+const BLANK: FormState = { name: '', consumable: '', category: '', unit: DEFAULT_UNIT, price: '', stock: '', alertThreshold: '' };
 
 const digits = (v: string) => toEnglishDigits(v).replace(/\D/g, '');
 // group thousands: "1200000" → "1,200,000"
 const group = (v: string) => v.replace(/\B(?=(\d{3})+(?!\d))/g, ',');
 
-/** «افزودن/ویرایش کالای جدید» — mirrors tauri ModalAddInventory field-for-field. */
-export default function AddItemModal({ open, editing, saving, onClose, onSave }: Props) {
+/** «افزودن/ویرایش کالای جدید» — واحد و دسته‌بندی از لیست استاندارد Backend. */
+export default function AddItemModal({ open, editing, meta, saving, onClose, onSave }: Props) {
   const [form, setForm] = useState<FormState>(BLANK);
   const [error, setError] = useState('');
 
@@ -38,7 +42,8 @@ export default function AddItemModal({ open, editing, saving, onClose, onSave }:
       ? {
           name: editing.name,
           consumable: editing.consumable ?? '',
-          unit: editing.unit,
+          category: editing.category ?? '',
+          unit: editing.unit || DEFAULT_UNIT,
           price: editing.price ? String(rialToToman(editing.price)) : '',
           stock: String(editing.stock),
           alertThreshold: String(editing.alertThreshold),
@@ -50,13 +55,17 @@ export default function AddItemModal({ open, editing, saving, onClose, onSave }:
     setForm((f) => ({ ...f, [k]: e.target.value }));
   const setNum = (k: keyof FormState) => (e: React.ChangeEvent<HTMLInputElement>) =>
     setForm((f) => ({ ...f, [k]: digits(e.target.value) }));
+  const setSelect = (k: keyof FormState) => (v: string | number | null) =>
+    setForm((f) => ({ ...f, [k]: v == null ? '' : String(v) }));
 
   const submit = () => {
     if (form.name.trim() === '') { setError('نام کالا الزامی است'); return; }
+    if (form.category === '') { setError('دسته‌بندی کالا الزامی است'); return; }
     const payload: ItemPayload = {
       name: form.name.trim(),
       consumable: form.consumable.trim() || null,
-      unit: form.unit.trim() || 'عدد',
+      category: form.category,
+      unit: form.unit || DEFAULT_UNIT,
       price: form.price ? tomanToRial(Number(form.price)) : 0,
       stock: form.stock ? Number(form.stock) : 0,
       alertThreshold: form.alertThreshold ? Number(form.alertThreshold) : 0,
@@ -64,19 +73,47 @@ export default function AddItemModal({ open, editing, saving, onClose, onSave }:
     onSave(payload, editing?.uuid);
   };
 
-  const fields: { key: keyof FormState; label: string; placeholder: string; numeric?: boolean }[] = [
+  const inputs: { key: keyof FormState; label: string; placeholder: string; numeric?: boolean }[] = [
     { key: 'name', label: 'نام کالا', placeholder: 'نام کالا' },
     { key: 'consumable', label: 'مصرفی', placeholder: 'مصرفی' },
-    { key: 'unit', label: 'واحد', placeholder: 'عدد' },
     { key: 'price', label: 'قیمت (تومان)', placeholder: 'قیمت', numeric: true },
     { key: 'stock', label: 'موجودی', placeholder: 'موجودی', numeric: true },
     { key: 'alertThreshold', label: 'هشدار اتمام', placeholder: 'هشدار اتمام', numeric: true },
   ];
 
+  const toOptions = (list: string[]) => list.map((v) => ({ value: v, label: v }));
+
   return (
     <Modal open={open} onClose={onClose} title={editing ? 'ویرایش کالا' : 'افزودن کالای جدید'} size="lg">
       <div style={{ display: 'flex', flexDirection: 'column', gap: 20 }}>
-        {fields.map((f) => (
+        <div>
+          <label className="field-label">نام کالا</label>
+          <div className="field">
+            <input value={form.name} onChange={set('name')} placeholder="نام کالا" autoFocus />
+          </div>
+        </div>
+
+        <div>
+          <label className="field-label">دسته‌بندی</label>
+          <SearchableSelect
+            options={toOptions(meta.categories)}
+            value={form.category || null}
+            onChange={setSelect('category')}
+            placeholder="انتخاب دسته‌بندی"
+          />
+        </div>
+
+        <div>
+          <label className="field-label">واحد</label>
+          <SearchableSelect
+            options={toOptions(meta.units)}
+            value={form.unit || DEFAULT_UNIT}
+            onChange={setSelect('unit')}
+            placeholder="انتخاب واحد"
+          />
+        </div>
+
+        {inputs.filter((f) => f.key !== 'name').map((f) => (
           <div key={f.key}>
             <label className="field-label">{f.label}</label>
             <div className="field">
@@ -85,7 +122,6 @@ export default function AddItemModal({ open, editing, saving, onClose, onSave }:
                 onChange={f.numeric ? setNum(f.key) : set(f.key)}
                 placeholder={f.placeholder}
                 inputMode={f.numeric ? 'numeric' : undefined}
-                autoFocus={f.key === 'name'}
               />
             </div>
           </div>

assets/admin/components/inventory/InventoryItemsTable.tsx

@@ -11,7 +11,7 @@ interface Props {
   onDelete: (item: InventoryItem) => void;
 }
 
-const HEAD = ['نام کالا', 'موجودی', 'واحد', 'قیمت', 'وضعیت', 'عملیات'];
+const HEAD = ['نام کالا', 'دسته‌بندی', 'موجودی', 'واحد', 'قیمت', 'وضعیت', 'عملیات'];
 
 /** Consumable-items list: desktop table + mobile card grid (tauri InventoryList). */
 export default function InventoryItemsTable({ items, onEdit, onDelete }: Props) {
@@ -30,6 +30,7 @@ export default function InventoryItemsTable({ items, onEdit, onDelete }: Props)
             {items.map((item) => (
               <tr key={item.uuid}>
                 <td style={{ color: 'var(--text-2)' }}>{item.name}</td>
+                <td style={{ color: 'var(--text-3)' }}>{item.category ?? '—'}</td>
                 <td>{formatNumber(item.stock)}</td>
                 <td>{item.unit}</td>
                 <td>{formatRial(item.price)}</td>
@@ -59,6 +60,7 @@ export default function InventoryItemsTable({ items, onEdit, onDelete }: Props)
               <InventoryStatusBadge status={item.status} />
             </div>
             {[
+              ['دسته‌بندی:', item.category ?? '—'],
               ['موجودی:', formatNumber(item.stock)],
               ['واحد:', item.unit],
               ['قیمت:', formatRial(item.price)],