fix(relation refs): buildRefs 跳过空串关联 id，避免可选 Relation 存 "" 时 $in 转 ObjectId 抛 CastError 整页 500

v0.7.11 误改在废弃的 _label/populateItems（无调用方）上：列表实际走 list()->buildRefs()。
本次回退 populateItems，改在真正活路径 collectOne。bump 0.7.12

package.json

@@ -1,6 +1,6 @@
 {
     "name": "shrimp-server",
-    "version": "0.7.10",
+    "version": "0.7.12",
     "description": "Shrimp 框架后端 — 声明式字段驱动的 Node.js 管理后台框架(Express + Mongoose + JWT)",
     "main": "dist/main/index.js",
     "types": "dist/main/index.d.ts",

src/Shrimp/ShrimpTableModule.ts

@@ -292,7 +292,8 @@ export class ShrimpTableModule<T, P extends ITableCrudProto<T> = ITableCrudProto
     private collectOne(f: IFieldConfig, v: any, add: (moduleKey: string, labelKey: string, id: any) => void): void {
         if (v == null) return
         if (f.type === "relation" && f.relation) {
-            ;(Array.isArray(v) ? v : [v]).forEach((id: any) => id != null && add(f.relation!.moduleKey, f.relation!.labelKey, id))
+            // 跳过空串：可选 Relation 常存 ""，混进 { _id: { $in } } 会让 Mongoose 转 ObjectId 抛 CastError、整页 500。
+            ;(Array.isArray(v) ? v : [v]).forEach((id: any) => id != null && id !== "" && add(f.relation!.moduleKey, f.relation!.labelKey, id))
         } else if (f.type === ShrimpFieldTypes.Tab && Array.isArray(f.tabs) && typeof v === "object") {
             const branch = f.tabs.find(t => t.key === v.type)
             if (branch) for (const c of branch.fields) this.collectOne(c, v[c.key], add)