fix(client): Windows main.cpp 用 ASCII 十六进制转义写标题，修复 C4819

v1.0.14 Windows 构建失败：main.cpp 含中文（u8 标题+中文注释），MSVC 在
GBK(936) 代码页报 C4819「字符无法表示」，而 runner 开了 /WX 警告即错误。
改为标题用 UTF-8 字节的 \x 十六进制转义、注释改英文，源码纯 ASCII，
运行时 MultiByteToWideChar(CP_UTF8) 解码，窗口标题仍是岩美酒库。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [1.0.14] - 2026-06-05
+## [1.0.15] - 2026-06-05
 
 ### 修复
 - 修复 Windows 桌面端打印卡死：打印字体由 OpenType/CFF 改为 TrueType(glyf)，dart_pdf 渲染中文不再抛错（此前点「打印」后卡死）

client/windows/runner/main.cpp

@@ -29,8 +29,11 @@ int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
   FlutterWindow window(project);
   Win32Window::Point origin(10, 10);
   Win32Window::Size size(1280, 720);
-  // 窗口标题：用 u8 字面量 + UTF-8→UTF-16 转换，避免源码编码导致中文乱码。
-  const std::string title_utf8 = u8"岩美酒库";
+  // Window title as UTF-8 bytes (hex-escaped to keep this source pure ASCII and
+  // avoid MSVC C4819 under GBK code page 936). Decoded to UTF-16 for Win32.
+  // Bytes below are the UTF-8 encoding of the Chinese app title.
+  const std::string title_utf8 =
+      "\xE5\xB2\xA9\xE7\xBE\x8E\xE9\x85\x92\xE5\xBA\x93";
   int title_len = ::MultiByteToWideChar(CP_UTF8, 0, title_utf8.c_str(), -1,
                                         nullptr, 0);
   std::wstring window_title(title_len > 0 ? title_len - 1 : 0, L'\0');