feat(wizard): cache مشخصه globally instead of per topic/category/brand

The specs combobox drew only from materials in the selected topic, further
narrowed by the row's category and brand, so a spec was offered only when
some material in that topic shared the same category AND brand. On a new
quote the user therefore lost specs recorded in earlier quotes.

- api.specsList(): new global source reading the attribute-definitions
  registry (topic/category/brand independent)
- materialOptions('spec'): unions the registry, specs of all materials,
  and specs typed in sibling rows — no topic/category/brand filter
- EditModal: same global registry added to its spec options

Verified the registry endpoint returns labels and that the union includes
specs absent from material attributes (e.g. 'مسی').

frontend/src/pages/Wizard/Step2LineItems.tsx

@@ -75,10 +75,10 @@ export function materialOptions(
   field: "cat" | "brand" | "spec",
   allItems: ItemDraft[] = [],
   apiBrands: string[] = [],
+  apiSpecs: string[] = [],
 ): string[] {
   let list = materials.filter((m) => topic && normalize(m.topic) === normalize(topic));
   const cat = item.cat.trim();
-  const brand = item.brand.trim();
 
   const fromRows = (sel: (it: ItemDraft) => string | string[]): string[] => {
     const out = new Set<string>();
@@ -96,15 +96,21 @@ export function materialOptions(
     fromRows((it) => it.cat).forEach((c) => base.add(c));
     return [...base].sort((a, b) => a.localeCompare(b, "fa"));
   }
-  if (cat) list = list.filter((m) => normalize(m.category) === normalize(cat));
   if (field === "brand") {
+    // برند سراسری است — مستقل از تاپیک و دسته
     const allBrands = new Set(materials.map((m) => m.brand).filter(Boolean));
     apiBrands.forEach((b) => b && allBrands.add(b));
     fromRows((it) => it.brand).forEach((b) => allBrands.add(b));
     return [...allBrands].sort((a, b) => a.localeCompare(b, "fa"));
   }
-  if (brand) list = list.filter((m) => normalize(m.brand) === normalize(brand));
-  const base = new Set(list.flatMap((m) => (m.specs || []).filter(Boolean)));
+  if (cat) list = list.filter((m) => normalize(m.category) === normalize(cat));
+  // مشخصه‌ها سراسری هستند: رجیستری attribute-definitions + مشخصه‌های همه‌ی
+  // متریال‌ها + مشخصه‌های تایپ‌شده در سایر ردیف‌ها. به تاپیک/دسته/برندِ قلمِ
+  // فعلی گره نمی‌خورند تا هنگام افزودن پیشنهاد جدید همیشه در دسترس باشند.
+  const base = new Set<string>();
+  apiSpecs.forEach((s) => s && base.add(s));
+  materials.forEach((m) => (m.specs || []).forEach((s) => s && base.add(s)));
+  list.forEach((m) => (m.specs || []).forEach((s) => s && base.add(s)));
   fromRows((it) => it.specs).forEach((s) => base.add(s));
   return [...base].sort((a, b) => a.localeCompare(b, "fa"));
 }
@@ -135,6 +141,7 @@ export function Step2LineItems({ items, onItemsChange, selectedTopic, onRemember
   }, [materials]);
 
   const [brandOptions, setBrandOptions] = useState<string[]>([]);
+  const [specOptions, setSpecOptions] = useState<string[]>([]);
 
   useEffect(() => {
     let alive = true;
@@ -150,6 +157,10 @@ export function Step2LineItems({ items, onItemsChange, selectedTopic, onRemember
       .brandsList()
       .then((list) => alive && setBrandOptions(list.map((b) => b.name).filter(Boolean)))
       .catch(() => {});
+    void api
+      .specsList()
+      .then((list) => alive && setSpecOptions(list))
+      .catch(() => {});
     return () => { alive = false; };
   }, []);
 
@@ -240,7 +251,7 @@ export function Step2LineItems({ items, onItemsChange, selectedTopic, onRemember
             <MultiSelectCombobox
               values={it.specs}
               onChange={(specs) => patch(it.tempId, { specs })}
-              options={materialOptions(materials, selectedTopic, it, "spec", items)}
+              options={materialOptions(materials, selectedTopic, it, "spec", items, [], specOptions)}
               placeholder="مشخصه"
               className="min-w-0"
             />