feat(export): 批量导出后生成 AI 穿搭 Excel，每印花子目录一行 (§17.23)

添加印花批量导出完成后，自动在输出目录生成与时间戳目录同名的 xlsx
文件（docs/02 §6.12）；每个有效印花子目录一行，C 列指向该子目录路径，
AI 穿搭页直接选取即可触发目录扇出逻辑（§19.12），无需手工填写 Excel。

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

tests/test_excel_service.py

@@ -138,6 +138,54 @@ class TestOutfitExcelService(unittest.TestCase):
             with self.assertRaises(ExcelInUseError):
                 ensure_excel_writable(self.excel_path)
 
+    # -- write_outfit_source_excel (docs/02 §6.12) ----------------------------
+
+    def test_write_outfit_source_excel_header_and_rows(self):
+        """One row per (print_name, subdir_path); header + A/B/C values correct."""
+        import os
+        from services.excel_service import write_outfit_source_excel
+
+        p = self.tmp / "batch.xlsx"
+        rows = [
+            ("floral", r"D:\out\20260623\floral" + os.sep),
+            ("stripe", r"D:\out\20260623\stripe" + os.sep),
+        ]
+        write_outfit_source_excel(p, rows)
+
+        wb = load_workbook(str(p))
+        ws = wb.active
+        try:
+            self.assertEqual(
+                [ws.cell(1, c).value for c in range(1, 7)],
+                ["标题", "货号", "衣服图路径", "生成结果图片路径", "完成状态", "失败原因"],
+            )
+            self.assertEqual(ws.max_row, 3)   # 1 header + 2 data
+            self.assertEqual(ws.cell(2, 1).value, "floral")
+            self.assertIsNone(ws.cell(2, 2).value)          # 货号留空
+            self.assertIn("floral", ws.cell(2, 3).value)
+            self.assertTrue(ws.cell(2, 3).value.endswith(os.sep))
+            self.assertEqual(ws.cell(3, 1).value, "stripe")
+            for col in (4, 5, 6):                           # D/E/F 留空
+                self.assertIsNone(ws.cell(2, col).value)
+        finally:
+            wb.close()
+
+    def test_write_outfit_source_excel_ai_outfit_can_read_it(self):
+        """AI穿搭 read_all_rows picks up the generated Excel as a directory row."""
+        import os
+        from services.excel_service import read_all_rows, write_outfit_source_excel
+
+        subdir = self.tmp / "floral"
+        subdir.mkdir()
+        p = self.tmp / "batch.xlsx"
+        write_outfit_source_excel(p, [("floral", str(subdir) + os.sep)])
+
+        rows = read_all_rows(p)
+        self.assertEqual(len(rows), 1)
+        self.assertEqual(rows[0].title, "floral")
+        self.assertEqual(rows[0].product_id, "")
+        self.assertTrue(rows[0].garment_path.endswith(os.sep))
+
 
 if __name__ == "__main__":
     unittest.main()