diff --git a/src/__tests__/homeLayoutEditor.spec.ts b/src/__tests__/homeLayoutEditor.spec.ts
index 9cf37e6..4e89389 100644
--- a/src/__tests__/homeLayoutEditor.spec.ts
+++ b/src/__tests__/homeLayoutEditor.spec.ts
@@ -49,7 +49,10 @@ const TREE: CategoryTreeNode[] = [
     { id: 12, name: "媒体聚焦", type: 1, children: [] },
 ] as unknown as CategoryTreeNode[];
 
-async function mountEditor(configJson: string, opts?: { siteId?: number; portalUrl?: string }) {
+async function mountEditor(
+    configJson: string,
+    opts?: { siteId?: number; portalUrl?: string; siteIdRef?: ReturnType<typeof ref<number | undefined>> },
+) {
     const el = document.createElement("div");
     document.body.appendChild(el);
     const model = ref(configJson);
@@ -58,7 +61,7 @@ async function mountEditor(configJson: string, opts?: { siteId?: number; portalU
             render: () =>
                 h(HomeLayoutEditor, {
                     modelValue: model.value,
-                    siteId: opts?.siteId,
+                    siteId: opts?.siteIdRef ? opts.siteIdRef.value : opts?.siteId,
                     portalUrl: opts?.portalUrl,
                     "onUpdate:modelValue": (v: string) => (model.value = v),
                 }),
@@ -237,6 +240,54 @@ describe("HomeLayoutEditor - F2 三栏 + 预览 + 缩略图 + 自动编排（doc
     });
 });
 
+describe("HomeLayoutEditor - 栏目树加载与首用编排解耦（docs/20 返工 #1）", () => {
+    it("已有布局 + 有列表栏目 + siteId：栏目树仍无条件加载，数据栏目可勾选", async () => {
+        treeMock.send.mockResolvedValue(TREE);
+        const config = JSON.stringify({
+            home_layout: { version: 1, blocks: [{ id: "a1", type: "article_list", categoryIds: [11], style: "card", size: 8 }] },
+        });
+        const { el, model } = await mountEditor(config, { siteId: 1 });
+        // 树加载发生（幂等标记下 treeMock 恰好 1 次调用）
+        expect(treeMock.send).toHaveBeenCalledTimes(1);
+        (el.querySelector(".hle-row") as HTMLElement).click();
+        await settle();
+        const cats = fieldOf(el as HTMLElement, "数据栏目")!;
+        expect(cats).not.toBeNull();
+        expect(cats.querySelectorAll(".hle-cat").length).toBe(2);
+        expect(cats.textContent).toContain("校园时讯");
+        expect(cats.textContent).toContain("媒体聚焦");
+        // 已有布局不被自动编排改写
+        expect(JSON.parse(model.value).home_layout.blocks[0].id).toBe("a1");
+    });
+
+    it("siteId 晚于挂载到位（父级异步种入）：watch 补跑加载，数据栏目可用", async () => {
+        treeMock.send.mockResolvedValue(TREE);
+        const siteIdRef = ref<number | undefined>(undefined);
+        const config = JSON.stringify({
+            home_layout: { version: 1, blocks: [{ id: "a1", type: "article_list", categoryIds: [], style: "card", size: 8 }] },
+        });
+        const { el } = await mountEditor(config, { siteIdRef });
+        await settle();
+        // siteId 未到位时不请求
+        expect(treeMock.send).not.toHaveBeenCalled();
+        siteIdRef.value = 1;
+        await settle(6);
+        expect(treeMock.send).toHaveBeenCalledTimes(1);
+        (el.querySelector(".hle-row") as HTMLElement).click();
+        await settle();
+        const cats = fieldOf(el as HTMLElement, "数据栏目")!;
+        expect(cats.querySelectorAll(".hle-cat").length).toBe(2);
+    });
+
+    it("watch + onMounted 双触发下幂等：同 siteId 只请求一次", async () => {
+        treeMock.send.mockResolvedValue(TREE);
+        const siteIdRef = ref<number | undefined>(1);
+        await mountEditor(JSON.stringify({ logo: "/a.png" }), { siteIdRef });
+        await settle(6);
+        expect(treeMock.send).toHaveBeenCalledTimes(1);
+    });
+});
+
 describe("HomeLayoutEditor - D 组件属性面板（docs/20 D-1/D-8）", () => {
     it("stats_band：统计项三列编辑器（名称/数值/单位）渲染并可增行", async () => {
         const config = JSON.stringify({
diff --git a/src/views/cms/homeLayout/HomeLayoutEditor.vue b/src/views/cms/homeLayout/HomeLayoutEditor.vue
index 75a9168..11f6708 100644
--- a/src/views/cms/homeLayout/HomeLayoutEditor.vue
+++ b/src/views/cms/homeLayout/HomeLayoutEditor.vue
@@ -92,24 +92,36 @@ watch(
     { immediate: true },
 );
 
+/** 已完成树加载的站点 id（幂等标记；null=未加载或上次失败可重试） */
+let loadedTreeSiteId: number | null = null;
+
 async function loadTree() {
     if (!props.siteId) return;
+    // REWORK-DECISION: 幂等保护（返工清单 #1-3）——同一 siteId 已加载过不重复请求，避免 onMounted + watch 双触发；
+    // 请求失败则清标记允许后续重试
+    if (loadedTreeSiteId === props.siteId) return;
+    loadedTreeSiteId = props.siteId;
     treeLoading.value = true;
     try {
         tree.value = (await categoryApi.tree(props.siteId).send()) || [];
     } catch {
         tree.value = [];
+        loadedTreeSiteId = null;
     } finally {
         treeLoading.value = false;
     }
 }
 
-/** F2 首用自动编排：进入编辑器时无 home_layout 键（回落态）且站点有列表型栏目 → 静默生成初始序列 */
-async function autoGenOnFirstUse() {
-    if (parseHomeLayout(props.modelValue) || !props.siteId) {
-        return;
-    }
+/**
+ * 站点上下文就绪后的数据初始化（docs/20 返工 #1）：
+ * ① 只要 siteId 有值就无条件加载栏目树（「数据栏目/人物分组」数据源），与「是否首用自动编排」解耦；
+ * ② 首用自动编排（D-4）复用已加载的树，不再独立承担加载职责。
+ * siteId 由父级异步种入（晚于本组件挂载）时由 watch 补跑。
+ */
+async function initSiteData() {
+    if (!props.siteId) return;
     await loadTree();
+    if (parseHomeLayout(props.modelValue)) return;
     if (!blocks.value.length && flat.value.length) {
         blocks.value = genFromCategories(tree.value, props.modelValue).blocks;
         selectedId.value = null;
@@ -117,7 +129,13 @@ async function autoGenOnFirstUse() {
     }
 }
 
-onMounted(autoGenOnFirstUse);
+onMounted(initSiteData);
+watch(
+    () => props.siteId,
+    id => {
+        if (id) initSiteData();
+    },
+);
 
 // ===== 中栏：实时预览（iframe + 视口切换 + postMessage 近似模拟 + 手动刷新兜底）=====