Fix double POST on open position in embed shell mode.

Embed capture-phase form handler and allowManualOrderSubmit both submitted /add_order; skip custom forms and use a single fetch reload path.

Co-authored-by: Cursor <cursoragent@cursor.com>

static/instance_embed.js

@@ -14,6 +14,9 @@
   let navToken = 0;
   let loadingTab = false;
 
+  /** 自带校验后 form.submit() 的表单，勿在捕获阶段再 fetch 一份（会双发 POST） */
+  const CUSTOM_SUBMIT_FORM_IDS = new Set(["add-order-form", "key-form"]);
+
   function isEmbedShell() {
     return document.body && document.body.getAttribute("data-embed-shell") === "1";
   }
@@ -124,6 +127,26 @@
     return loadTab(getTab(), { replace: true, skipUrl: true });
   }
 
+  function postFormAndReload(form, label) {
+    if (!form) return Promise.resolve();
+    if (global.FormSubmitGuard) {
+      if (global.FormSubmitGuard.isLocked(form)) {
+        global.FormSubmitGuard.setSubmitLabel(form, label || "提交中…");
+      } else {
+        global.FormSubmitGuard.lock(form, label || "提交中…");
+      }
+    }
+    const fd = new FormData(form);
+    return fetch(form.action, {
+      method: form.method || "POST",
+      body: fd,
+      credentials: "same-origin",
+      redirect: "manual",
+    })
+      .then(() => reloadCurrentTab())
+      .catch(() => reloadCurrentTab());
+  }
+
   function patchApplyListWindow() {
     if (typeof global.applyListWindow !== "function") return;
     global.applyListWindow = function embedApplyListWindow() {
@@ -176,6 +199,7 @@
         const form = ev.target;
         if (!(form instanceof HTMLFormElement)) return;
         if (form.method && form.method.toUpperCase() === "GET") return;
+        if (CUSTOM_SUBMIT_FORM_IDS.has(form.id)) return;
         ev.preventDefault();
         const fd = new FormData(form);
         fetch(form.action, {
@@ -221,6 +245,7 @@
     loadTab,
     reloadCurrentTab,
     getTab,
+    postFormAndReload,
   };
 
   if (document.readyState === "loading") {