refactor(catalog)!: decouple materials from categories (v2.7)

Materials are now global and category-free. The category lives only on the supplier (suppliers.category_id); every category-facing query goes through the supplier edge instead of the material row.

Schema (migration.sql + init_db DDL):
- drop the materials.category_id column, its FK, and the v2.5 first-link-wins automation (fn_derive_material_category + trg_supplier_materials_derive_category) — the DDL runs idempotently at API startup

Backend:
- GET /materials?category_id=… now filters via EXISTS(supplier_materials ⋈ suppliers.category_id)
- quote category filters (quotes list) use the quote's supplier category
- /pm/on-the-way derives the display category from the supplier of the quote
- supplier_materials links no longer derive/return a material category
- expand_service: material expand=category resolves to null (kept for contract compatibility)
- material create/update no longer validates or stores category_id; seed.py aligned

Frontend:
- material creation no longer sends category_id
- formatMaterialTitle reworked to a strict order with « . » separator: [Brand] . [Material] . [Spec 1] . [Spec 2], brand deduped when the stored name already starts with it; specs separator switched from « · » to « . »

Validated: python compile, api + frontend image builds (tsc + vite) clean; branch cut from the tip of prod_v4 (= origin/production, 5a9ef40 — the team's merge made them identical).

frontend/src/lib/quoteUtils.ts

@@ -35,43 +35,51 @@ export function specsKey(specs: string[]): string {
   return (specs || []).map((s) => normalize(s)).filter(Boolean).sort().join("|");
 }
 
-// specها با جداکننده‌ی « · »
+// specها با جداکننده‌ی « . »
 export function specsLabel(specs: string[]): string {
-  return specs.join(" · ");
+  return specs.join(" . ");
 }
 
 /**
  * عنوان تمیز و بدون تکرار کالا:
- * ترکیب هوشمندانه‌ی نام اصلی (materials.name)، برند، و مشخصه‌ها بدون تکرار کلمات مشترک.
+ * ترتیب اکید با جداکننده‌ی نقطه:
+ * [نام برند] . [نام متریال] . [مشخصه ۱] . [مشخصه ۲]
  */
 export function formatMaterialTitle(
   m: Pick<Material, "name" | "brand" | "specs" | "category"> | null | undefined,
   extraSpecs?: string[],
 ): string {
   if (!m) return "کالا";
-  const rawName = (m.name || "").trim();
+  let rawName = (m.name || "").trim();
   const rawBrand = (m.brand || "").trim();
   const rawSpecs = [...(m.specs || []), ...(extraSpecs || [])]
     .map((s) => (s || "").trim())
     .filter(Boolean);
 
-  const normName = normalize(rawName);
   const normBrand = normalize(rawBrand);
 
-  if (!rawName) {
-    if (rawBrand && rawSpecs.length) return `${rawBrand} · ${rawSpecs.join(" · ")}`;
-    if (rawBrand) return rawBrand;
-    if (rawSpecs.length) return rawSpecs.join(" · ");
-    return m.category && m.category !== "؟" ? m.category : "کالا";
+  // اگر نام کالا با نام برند شروع شده باشد، برند را از ابتدای نام برمی‌داریم تا تکرار نشود
+  if (normBrand && rawName) {
+    const normName = normalize(rawName);
+    if (normName.startsWith(normBrand)) {
+      const rest = rawName.slice(rawBrand.length).trim();
+      rawName = rest.replace(/^[.\s·\-]+/, "").trim();
+    }
   }
 
-  let title = rawName;
-  if (normBrand && !normName.includes(normBrand)) {
-    title = `${rawBrand} ${title}`;
+  // قطعات نهایی با ترتیب مشخص: [Brand Name] . [Material Name] . [Specification 1] . [Specification 2]
+  const parts: string[] = [];
+  if (rawBrand) {
+    parts.push(rawBrand);
+  }
+  if (rawName) {
+    parts.push(rawName);
+  } else if (!rawBrand) {
+    parts.push(m.category && m.category !== "؟" ? m.category : "کالا");
   }
 
-  const normTitle = normalize(title);
-  const distinctSpecs: string[] = [];
+  // اضافه کردن مشخصه‌ها بدون تکرار
+  const normCurrent = normalize(parts.join(" "));
   const seenNormSpecs = new Set<string>();
 
   for (const s of rawSpecs) {
@@ -79,15 +87,12 @@ export function formatMaterialTitle(
     if (!ns || seenNormSpecs.has(ns)) continue;
     seenNormSpecs.add(ns);
 
-    // اگر مشخصه قبلاً داخل عنوان یا نام کالا آمده باشد، تکرار نمی‌کنیم
-    if (normTitle.includes(ns)) continue;
-    distinctSpecs.push(s);
+    // اگر مشخصه قبلاً داخل نام یا برند آمده باشد، تکرار نمی‌کنیم
+    if (normCurrent.includes(ns)) continue;
+    parts.push(s);
   }
 
-  if (distinctSpecs.length > 0) {
-    return `${title} · ${distinctSpecs.join(" · ")}`;
-  }
-  return title;
+  return parts.join(" . ");
 }
 
 export function materialLabel(m: Pick<Material, "name" | "brand" | "specs" | "category"> | null | undefined): string {