Add Excel export feature for full production data

Add "导出全部" button that exports all contract production data to an
.xlsx file via a new API endpoint using exceljs, with formatted headers,
date columns, auto-width, and frozen header row.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/page.tsx

@@ -14,7 +14,7 @@ import {
   Checkbox,
   AutoComplete,
 } from "antd";
-import { SearchOutlined, SettingOutlined, HolderOutlined, ClockCircleOutlined } from "@ant-design/icons";
+import { SearchOutlined, SettingOutlined, HolderOutlined, ClockCircleOutlined, DownloadOutlined } from "@ant-design/icons";
 import type { ColumnsType } from "antd/es/table";
 import {
   DndContext,
@@ -333,6 +333,8 @@ function SearchBar({
   onSearch,
   onClear,
   onOpenColumnSettings,
+  exporting,
+  onExport,
 }: {
   loading: boolean;
   resultCount: number;
@@ -340,6 +342,8 @@ function SearchBar({
   onSearch: (workshopNo: string) => Promise<void>;
   onClear: () => void;
   onOpenColumnSettings: () => void;
+  exporting: boolean;
+  onExport: () => void;
 }) {
   const [inputValue, setInputValue] = useState("");
   const [history, setHistory] = useState<string[]>(() => loadHistory());
@@ -418,6 +422,13 @@ function SearchBar({
         <Button icon={<SettingOutlined />} onClick={onOpenColumnSettings}>
           列设置
         </Button>
+        <Button
+          icon={<DownloadOutlined />}
+          onClick={onExport}
+          loading={exporting}
+        >
+          导出全部
+        </Button>
       </Space>
       {searched && !loading && (
         <Text type="secondary" style={{ marginLeft: 16 }}>
@@ -438,6 +449,7 @@ export default function Home() {
   const [searched, setSearched] = useState(false);
   const [columnConfig, setColumnConfig] = useState<ColumnConfig[]>(loadConfig);
   const [modalOpen, setModalOpen] = useState(false);
+  const [exporting, setExporting] = useState(false);
 
   // Persist config
   useEffect(() => {
@@ -473,6 +485,31 @@ export default function Home() {
     setError(null);
   }, []);
 
+  const handleExport = useCallback(async () => {
+    setExporting(true);
+    try {
+      const res = await fetch("/api/export-excel");
+      if (!res.ok) {
+        const json = await res.json().catch(() => null);
+        setError(json?.error || "导出失败");
+        return;
+      }
+      const blob = await res.blob();
+      const url = URL.createObjectURL(blob);
+      const a = document.createElement("a");
+      a.href = url;
+      a.download = "压力表合同生产数据.xlsx";
+      document.body.appendChild(a);
+      a.click();
+      document.body.removeChild(a);
+      URL.revokeObjectURL(url);
+    } catch {
+      setError("导出请求失败");
+    } finally {
+      setExporting(false);
+    }
+  }, []);
+
   const handleApplyConfig = useCallback((newConfig: ColumnConfig[]) => {
     setColumnConfig(newConfig);
     setModalOpen(false);
@@ -500,6 +537,8 @@ export default function Home() {
         onSearch={handleSearch}
         onClear={handleClear}
         onOpenColumnSettings={() => setModalOpen(true)}
+        exporting={exporting}
+        onExport={handleExport}
       />
 
       <div style={{ flex: 1, minHeight: 0 }}>