Add record-detail helpers (title picker, cell formatter)

src/app/record-detail.test.ts

@@ -0,0 +1,41 @@
+import { describe, it, expect } from "vitest";
+import { pickRecordTitle, formatCellValue } from "./record-detail";
+import type { DataRow } from "./table-filters";
+
+describe("pickRecordTitle", () => {
+  it("prefers 生产订单号", () => {
+    const row: DataRow = { 生产订单号: "PO-1", 总排号: "X", ID: 1 };
+    expect(pickRecordTitle(row)).toBe("PO-1");
+  });
+  it("falls back to 总排号 when 生产订单号 blank", () => {
+    const row: DataRow = { 生产订单号: "  ", 总排号: "X-9", ID: 1 };
+    expect(pickRecordTitle(row)).toBe("X-9");
+  });
+  it("falls back to ID when earlier are null/empty", () => {
+    const row: DataRow = { 生产订单号: null, 总排号: "", ID: 42 };
+    expect(pickRecordTitle(row)).toBe("42");
+  });
+  it("returns （未命名） when all blank", () => {
+    const row: DataRow = { 生产订单号: null, 总排号: null, ID: null };
+    expect(pickRecordTitle(row)).toBe("（未命名）");
+  });
+});
+
+describe("formatCellValue", () => {
+  it("null -> em dash", () => {
+    expect(formatCellValue(null)).toBe("—");
+  });
+  it("empty / whitespace -> em dash", () => {
+    expect(formatCellValue("")).toBe("—");
+    expect(formatCellValue("   ")).toBe("—");
+  });
+  it("0 is NOT blank", () => {
+    expect(formatCellValue(0)).toBe("0");
+  });
+  it("number stringified", () => {
+    expect(formatCellValue(123)).toBe("123");
+  });
+  it("text preserved", () => {
+    expect(formatCellValue("量程0-1.6MPa")).toBe("量程0-1.6MPa");
+  });
+});