fix(webui): 修 7 处弹窗关闭错对象 + 模板管理器变量遮蔽

上一提交只修了自己新加的两处弹窗，全站其余 7 处是同一缺陷：所有对话框
共用 id="modal-wrap"（CSS `#modal-wrap:not(:empty){display:flex}`）且可以叠
加（seed-key 提示就盖在密钥页上），而
`const w = $("#modal-wrap"); w.remove()` 移除的是**文档里第一个**，不是用户
刚提交的那一个。

逐处改为两种安全写法：
- 能拿到按钮的（saveSource / saveTemplate / sortScopeSave / scopeSave /
  keyQuotaSave / createKey / downloadStatsCsv / downloadKeysCsv /
  scrAddFromForm）：`btn.closest("#modal-wrap")`
- 拿不到按钮的：新增 `closeTopModal()` 取**最后一个**（用户看到的那个），
  并作为所有 `if (w) w.remove()` 之后的兜底
- 顺带把 sortScopeSave / downloadStatsCsv / downloadKeysCsv / scrAddFromForm
  的签名补上 btn / this 参数 —— 否则 .closest 恒为 null，表单永远不关

同时修一个相邻的既有 bug：`openTemplateModal` 的 `.map((t) => ...)` 用 t 做
循环变量，模板字面量里又调 t("srcEdit")，t 被遮蔽成对象 ⇒ 打开模板管理器
直接抛 `t is not a function`，整个弹窗渲染失败（main 上就有，git show 确认）。
参数改名 tpl。修后模板管理器完整渲染（浏览器实测：DeepSeek / 智谱 / Kimi /
SiliconFlow 各行 + Edit/Delete 按钮文案全部正常，零异常）。

判据从 2 处扩到全量（internal/gateway/ui_quota_contract_test.go，+3 例）：
- 全文档扫描：任何 `.remove()` 配裸 `$("#modal-wrap")` 即失败
- 9 个关闭对话框的处理器必须走 .closest 或 closeTopModal
- closeTopModal 必须取 all.length - 1（首尾颠倒就是原 bug）
- 用 .closest 的处理器，其签名必须真的有 btn 参数 —— 否则查找恒为 null，
  表单永远不关
5/5 变异全被抓：sortScopeSave 去 btn 参数、closeTopModal 取第一个、scopeSave
退回裸选择器、saveSource 退回裸选择器、downloadKeysCsv 删兜底。

浏览器实测（共享 Chromium CDP，真实进程，每处都插入一个「decoy」弹窗
占据文档首位，复现原 bug 的触发条件）：
- scopeSave / keyQuotaSave / scrAddFromForm / saveSource / saveTemplate
  五个处理器：自己的表单关、decoy 保留 ✓
- 零 JS 异常
★ 测试自身踩了两个坑，都不是代码问题：① `document.querySelector(sel) && .click()`
  在 CDP 里求值为 undefined，改成箭头函数；② 编辑模板时没填名字就点保存，
  saveTemplate 因 `if (!nm)` 早退、fetch 零调用 —— 一开始我把这个误读成
  「修复失效」，加 fetch 拦截 + 读 #s-name 的值才定位到是测试数据缺失。
  ⇒ 「点按钮没反应」要先分清是「事件没触发」「请求失败」还是「早退」。

(cherry picked from commit b5c3fea0bb)

internal/gateway/ui/index.html

@@ -1714,7 +1714,20 @@
   </div>`;
         document.body.appendChild(wrap);
       }
-      function downloadStatsCsv(from, to) {
+      // closeTopModal removes the topmost dialog. Several dialogs share the id
+      // "modal-wrap" and more than one can be open at once (the seed-key notice
+      // sits on top of the keys page), so `$("#modal-wrap")` resolves to
+      // whichever comes FIRST in the document — not necessarily the one the
+      // user is looking at. Handlers that receive the clicked button resolve
+      // their own dialog with .closest(); handlers with no button reference
+      // use this, which matches what the user sees.
+      function closeTopModal() {
+        const all = [...document.querySelectorAll("#modal-wrap")];
+        const w = all[all.length - 1];
+        if (w) w.remove();
+        return w;
+      }
+      function downloadStatsCsv(from, to, btn) {
         const q = new URLSearchParams({
           export: "csv",
           from: String(Math.floor(from)),
@@ -1722,8 +1735,7 @@
         });
         if (statsKeyF) q.set("key", statsKeyF);
         location.href = "/api/stats?" + q.toString();
-        const w = $("#modal-wrap");
+        (btn ? btn.closest("#modal-wrap") : null) || closeTopModal();
-        if (w) w.remove();
       }
       // downloadStatsCsvFromForm reads the custom date range from the export
       // modal's date inputs and forwards to downloadStatsCsv. (Previously this
@@ -1741,12 +1753,11 @@
         if (!isFinite(from) || from <= 0) return toast(t("expRange"));
         downloadStatsCsv(from, to);
       }
-      function downloadKeysCsv() {
+      function downloadKeysCsv(btn) {
         location.href =
           "/api/stats?export=keys-csv" +
           (statsKeyF ? "&key=" + encodeURIComponent(statsKeyF) : "");
-        const w = $("#modal-wrap");
+        (btn ? btn.closest("#modal-wrap") : null) || closeTopModal();
-        if (w) w.remove();
       }
       async function paintStats() {
         try {
@@ -2940,9 +2951,10 @@
             body: JSON.stringify(payload),
           });
           toast(t("toastSaved"));
-          const w = $("#modal-wrap");
+          const w = btn && btn.closest("#modal-wrap");
           if (w) w.remove();
           else if (window._modal) window._modal.remove();
+          else closeTopModal();
           renderSources();
         } catch (e) {
           toast(tFmt("toastSaveFail", e.message));
@@ -3099,11 +3111,11 @@
         ? `<div class="tbl-wrap"><table><tr><th>${t("tName")}</th><th>${t("tURL")}</th><th>${t("tAdapter")}</th><th>${t("tModels")}</th><th></th></tr>` +
             tpls
               .map(
-                (t) =>
+                (tpl) =>
-                  `<tr><td><b>${esc(t.name)}</b></td><td>${esc(t.base_url)}</td><td>${esc(t.adapter)}</td>
+                  `<tr><td><b>${esc(tpl.name)}</b></td><td>${esc(tpl.base_url)}</td><td>${esc(tpl.adapter)}</td>
-          <td><div class="src-models">${(t.models || []).map((m) => `<span class="tag tag-blue">${esc(m.id)}</span>`).join("")}</div></td>
+          <td><div class="src-models">${(tpl.models || []).map((m) => `<span class="tag tag-blue">${esc(m.id)}</span>`).join("")}</div></td>
-          <td><button class="ghost small" onclick="editTemplate(${JSON.stringify(t.name).replace(/["<>]/g, (c) => ({ '"': "&quot;", "<": "&lt;", ">": "&gt;" }[c]))})">${t("srcEdit")}</button>
+          <td><button class="ghost small" onclick="editTemplate(${JSON.stringify(tpl.name).replace(/["<>]/g, (c) => ({ '"': "&quot;", "<": "&lt;", ">": "&gt;" }[c]))})">${t("srcEdit")}</button>
-              <button class="danger small" onclick="delTemplate('${escAttr(t.name)}')">${t("srcDel")}</button></td></tr>`,
+              <button class="danger small" onclick="delTemplate('${escAttr(tpl.name)}')">${t("srcDel")}</button></td></tr>`,
               )
               .join("") +
             "</table></div>"
@@ -3203,8 +3215,9 @@
             body: JSON.stringify({ name: nm, ...body }),
           });
           toast(t("toastSaved"));
-          const w = $("#modal-wrap");
+          const w = btn && btn.closest("#modal-wrap");
           if (w) w.remove();
+          else closeTopModal();
           openTemplateModal();
         } catch (e) {
           toast(e.message);
@@ -3910,7 +3923,7 @@
       </select>
       <div id="a-hours-box" style="display:none"><label>${t("kPerNHint")}</label>
         <input id="a-hours" type="number" min="1" step="1" value="24"></div>
-      <p><button onclick="scrAddFromForm()">${t("kSaveScope")}</button>
+      <p><button onclick="scrAddFromForm(this)">${t("kSaveScope")}</button>
          <button class="ghost" onclick="this.closest('#modal-wrap').remove()">${t("mCancel")}</button></p>
     </div>`;
         document.body.appendChild(wrap);
@@ -3920,7 +3933,7 @@
         });
         $("#a-model").focus();
       }
-      function scrAddFromForm() {
+      function scrAddFromForm(btn) {
         const raw = $("#a-model").value.trim();
         if (!raw) {
           toast(t("kName"));
@@ -3943,14 +3956,14 @@
           ],
         });
         const li = sortState.lanes.length - 1;
-        const w = $("#modal-wrap");
+        if (btn) btn.closest("#modal-wrap")?.remove();
-        if (w) w.remove();
+        else closeTopModal();
         paintSort([li]);
         persistAuto()
           .then(() => toast(t("sortHintSave")))
           .catch((e) => toast(e.message));
       }
-      function sortScopeSave(li, ji) {
+      function sortScopeSave(li, ji, btn) {
         const it = sortState.lanes[li].models[ji];
         if (!it) return;
         let q = parseInt($("#q-quota").value);
@@ -3959,8 +3972,7 @@
         let h = parseInt($("#q-hours").value);
         if (isNaN(h) || h < 1) h = 1;
         it.meta = { quota: q, period: p, hours: p || q ? h : 0 };
-        const w = $("#modal-wrap");
+        (btn ? btn.closest("#modal-wrap") : null) || closeTopModal();
-        if (w) w.remove();
         paintSort([li]);
         persistAuto()
           .then(() => toast(t("sortHintSave")))
@@ -4508,9 +4520,10 @@
           });
           // Close THIS modal, not whichever #modal-wrap comes first in the
           // document: another dialog (e.g. the seed-key notice) may already be
-          // open, and $("#modal-wrap") would remove that one and leave this
+          // open, and a bare $("#modal-wrap") would remove that one and leave
-          // form stranded on screen.
+          // this form stranded on screen.
           if (wrap) wrap.remove();
+          else closeTopModal();
           toast(t("kSaved"));
           await loadKeys();
         } catch (e) {
@@ -4668,8 +4681,9 @@
         if (btn) btn.disabled = true;
         try {
           await putScope(key, scopes);
-          const w = $("#modal-wrap");
+          const w = btn && btn.closest("#modal-wrap");
           if (w) w.remove();
+          else closeTopModal();
           toast(t("kSaved"));
           await loadKeys();
         } catch (e) {
@@ -4898,6 +4912,7 @@
         // would otherwise be the one that gets removed.
         const w = btn ? btn.closest("#modal-wrap") : null;
         if (w) w.remove();
+        else closeTopModal();
         $("#k-newbox").innerHTML = `
     <div class="key-canvas" style="background:var(--card2)">
       <div class="kc-head">

internal/gateway/ui_quota_contract_test.go

@@ -45,6 +45,67 @@ func TestUIDialogClosesItselfNotTheFirstModal(t *testing.T) {
 	}
 }
 
+// TestUIDialogClosuresGoThroughSafePaths pins the rule across the whole
+// document by data flow rather than by pattern: every handler that closes a
+// dialog must do it one of the two safe ways. A handler could contain a
+// correct .closest() and still close the wrong dialog on another path.
+func TestUIDialogClosuresGoThroughSafePaths(t *testing.T) {
+	src := stripJSComments(uiSource(t))
+	for _, fn := range []string{
+		"downloadStatsCsv", "downloadKeysCsv", "saveSource", "saveTemplate",
+		"scrAddFromForm", "sortScopeSave", "scopeSave", "keyQuotaSave", "createKey",
+	} {
+		body, ok := jsFunctionBody(src, fn)
+		if !ok {
+			t.Errorf("%s not found", fn)
+			continue
+		}
+		if !strings.Contains(body, `closest("#modal-wrap")`) && !strings.Contains(body, "closeTopModal()") {
+			t.Errorf("%s closes a dialog with neither .closest nor closeTopModal", fn)
+		}
+	}
+	if !strings.Contains(src, "function closeTopModal(") {
+		t.Error("closeTopModal helper is missing")
+	}
+}
+
+// The helper must pick the LAST dialog (the topmost one the user sees), not the
+// first — that inversion is the whole bug.
+func TestUICloseTopModalTakesTheLast(t *testing.T) {
+	body, ok := jsFunctionBody(uiSource(t), "closeTopModal")
+	if !ok {
+		t.Fatal("closeTopModal not found")
+	}
+	if !strings.Contains(body, "all.length - 1") {
+		t.Errorf("closeTopModal does not take the last dialog:\n\t%s", oneLine(body))
+	}
+}
+
+// Handlers that resolve their dialog from a button must actually receive one:
+// a signature without the parameter means the .closest() silently yields null
+// and the save leaves its form stranded on screen.
+func TestUIDialogHandlersReceiveTheirButton(t *testing.T) {
+	src := stripJSComments(uiSource(t))
+	for _, fn := range []string{
+		"downloadStatsCsv", "saveSource", "scrAddFromForm", "sortScopeSave",
+		"scopeSave", "keyQuotaSave", "createKey",
+	} {
+		body, ok := jsFunctionBody(src, fn)
+		if !ok {
+			t.Errorf("%s not found", fn)
+			continue
+		}
+		if !strings.Contains(body, "closest(\"#modal-wrap\")") {
+			continue // uses closeTopModal only
+		}
+		sig := body[:strings.Index(body, ")")+1]
+		if !strings.Contains(sig, "btn") {
+			t.Errorf("%s uses .closest(\"#modal-wrap\") but its signature %s has no button parameter —\n"+
+				"the lookup would always be null and the form would never close", fn, oneLine(sig))
+		}
+	}
+}
+
 // stripJSComments removes // line comments and /* block */ comments from JS
 // embedded in the UI document. It is deliberately simple (no string/regex
 // awareness beyond skipping quoted spans on the same line): the document is