fix: 库存批次改为车型名称、区域待交车数量始终显示

- 库存统计：移除批次筛选（原显示contractNo），batch字段改为model
- 区域Tab：待交车和库存数量即使为0也显示数字，移除|| ''和if守卫
- 桌面端和移动端的pendingCount/inventory全部始终显示

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/server/routes/vehicles.ts

@@ -970,15 +970,14 @@ app.get('/inventory-stats', async (c) => {
     const city = resolveCity(v.city, v.province);
     const brand = v.brandLabel || '未知';
     const model = v.model;
-    const batch = v.contractNo || 'N/A';
-    const key = `${region}|${city}|${brand}|${typeName}|${model}|${batch}`;
+    const key = `${region}|${city}|${brand}|${typeName}|${model}`;
     groups.set(key, (groups.get(key) || 0) + 1);
   }
 
   const result = Array.from(groups.entries())
     .map(([key, quantity]) => {
-      const [region, city, brand, type, model, batch] = key.split('|');
-      return { region, city, brand, type, model, batch, quantity };
+      const [region, city, brand, type, model] = key.split('|');
+      return { region, city, brand, type, model, batch: model, quantity };
     })
     .sort((a, b) => b.quantity - a.quantity);