fix(ui): 优先级页的保存/重置/添加按钮每次打开都被画布渲染冲掉

renderSortEditor 会整体替换 mount 的 innerHTML。per-key AUTO 弹窗的 mount
只有画布，覆写无害；但全局优先级页把 .card（连同里面装着工具栏的 h2）当
mount 传了进去，于是每次打开页面，画布一渲染就把工具栏删了。

症状很隐蔽：泳道和积木照常渲染、拖拽也正常，只是「保存排序」「重置」
「+ 添加档位」和聊天/生图切换全部消失 —— 优先级变得无从调整，也无从保存。
DOM 里数画布元素一切正常，只有量按钮的几何尺寸才看得见它没了。

修法：工具栏留在 .card 里，另给一个 #sort-mount 专供画布。per-key 弹窗
本来就是这个结构，无需改动。

判据 1 条，断言工具栏必须落在 #sort-mount 之外，且 renderSortEditor 必须
接收 #sort-mount 而不是 .card。变异（mount 改回 .card）判红。

生产 CDP 实测（真实点击，非仅 DOM 断言）：
  5 个按钮全部可见，坐标尺寸正常（保存排序 72x29）
  画布 4 泳道 / 10 块
  点击「保存排序」→ toast「排序已保存并热重载 · 链上冷却已复位」
  切走再回来，按钮仍在位

Co-Authored-By: ModelRouter <noreply@modelrouter.dev>

internal/gateway/ui/index.html

@@ -3648,13 +3648,20 @@ recsState.keyNames = keyNames || {};
         sortState.origin = JSON.stringify(sortState.lanes);
         const kindToggle =
           `<div class="kind-toggle"><button class="${sortState.kind === "chat" ? "" : "ghost"} small" onclick="switchSortKind('chat')">${t("kChat") || "聊天"}</button><button class="${sortState.kind === "image" ? "" : "ghost"} small" onclick="switchSortKind('image')">${t("kImage") || "生图"}</button></div>`;
+        // renderSortEditor replaces its mount wholesale, so the mount must be
+        // the canvas slot ALONE. Passing the .card (which holds the h2 with the
+        // save/reset/add buttons) used to wipe the toolbar on every open — the
+        // lane canvas survived, the buttons did not. The per-key modal never hit
+        // this because its mount only ever contained the canvas.
         $("#tab-sort").innerHTML = `
-    <div class="card"><h2><span>${t("sortTitle")}</span><span class="grow"></span>${kindToggle}
+    <div class="card">
+      <h2><span>${t("sortTitle")}</span><span class="grow"></span>${kindToggle}
       <button class="ghost small" onclick="scrAddModal()">+ ${t("sortAdd")}</button>
       <button class="ghost small" onclick="sortReset()">${t("sortReset")}</button>
-<button class="small" onclick="saveSort()">${t("sortSave")}</button></h2>
+      <button class="small" onclick="saveSort()">${t("sortSave")}</button></h2>
+      <div id="sort-mount"></div>
     </div>`;
-        renderSortEditor($("#tab-sort").querySelector(".card"), {
+        renderSortEditor($("#sort-mount"), {
           canvasId: "scr-canvas",
         });
       }

internal/gateway/ui_key_auto_test.go

@@ -393,3 +393,46 @@ func TestAutoScopeConflictMessageComesFromCheckQuota(t *testing.T) {
 		t.Fatal("checkQuota's AUTO branch must name the scope as the cause")
 	}
 }
+
+// renderSortEditor replaces its mount's innerHTML wholesale. The global
+// priority page used to hand it the .card that also holds the h2 toolbar, so
+// every open deleted the save/reset/add buttons: the lanes still rendered and
+// the drag worked, but there was no way to persist a change. The per-key modal
+// never showed this because its mount held only the canvas.
+//
+// The regression is invisible in the DOM when you only count lane elements, so
+// this asserts on the structure: the toolbar lives in a sibling of the mount,
+// not inside it.
+func TestGlobalSortToolbarSurvivesCanvasRender(t *testing.T) {
+	src := uiSource(t)
+
+	// The global editor must mount into a dedicated host, not the .card.
+	i := strings.Index(src, `$("#tab-sort").innerHTML = `)
+	if i < 0 {
+		t.Fatal("global sort markup not found")
+	}
+	chunk := src[i:min(len(src), i+1400)]
+	if !strings.Contains(chunk, `id="sort-mount"`) {
+		t.Fatal("global sort page must provide a dedicated #sort-mount for the canvas")
+	}
+	// The mount handed to renderSortEditor must be that host.
+	if !strings.Contains(src, `renderSortEditor($("#sort-mount")`) {
+		t.Fatal("renderSortEditor must be given #sort-mount; passing the .card " +
+			"wipes the h2 toolbar that holds the save button")
+	}
+	// The toolbar (save in particular) must be OUTSIDE #sort-mount.
+	close := strings.Index(chunk, "</div>`;")
+	if close < 0 {
+		t.Fatal("malformed #tab-sort template")
+	}
+	head := chunk[:close]
+	mountAt := strings.Index(head, `id="sort-mount"`)
+	saveAt := strings.Index(head, `onclick="saveSort()"`)
+	if saveAt < 0 {
+		t.Fatal("the global sort page has no save button at all")
+	}
+	if mountAt >= 0 && saveAt > mountAt {
+		t.Fatal("the save button sits inside the canvas mount and will be " +
+			"erased the moment the canvas renders")
+	}
+}