refactor(theme): 以 TensentypeCode 单文件字体替换 GoogleSansCode 分片方案

[变更性质]
本提交为字体系统的重构，移除原有的 GoogleSansCode 5 分片方案，改为单文件 TensentypeCode 字体。

[重构动机]
原有方案依赖 5 个 woff2 分片（latin-base / latin-ext / cjk-common / cjk-ext / symbols）及 CarroisSong.ttf，
管理复杂且体积较大。统一替换为 TensentypeCode.woff2 单文件，简化字体加载链路。

[重构方案]
- 删除 themes/theme/source/fonts/ 下所有旧字体文件（5 个 woff2 分片 + CarroisSong.ttf + GoogleSansCode-Regular.ttf 源文件）
- font-slices.styl：将 5 个 @font-face 合并为单个，font-family 改为 'TensentypeCode'
- variable.styl：$font-family 改为 'TensentypeCode'
- head.ejs：preload 从两个分片改为单个 TensentypeCode.woff2
- source/fonts/ 新增 TensentypeCode.woff2 字体文件

[影响范围]
- 涉及主题层 CSS 变量、font-face 定义、HTML preload 三处修改
- 构建产物 fonts/ 目录从 ~6.3MB 降至 ~1.4MB
- 浏览器行为由 unicode-range 按需加载变为单文件整体加载，减少连接数但可能增加首次加载量

11 files changed, 7 insertions, 46 deletions

diff --git a/source/fonts/TensentypeCode.woff2 b/source/fonts/TensentypeCode.woff2
new file mode 100644
index 00000000..0659ed74
--- /dev/null
+++ b/source/fonts/TensentypeCode.woff2
diff --git a/themes/theme/layout/partials/head.ejs b/themes/theme/layout/partials/head.ejs
index 23265719..16be12f8 100644
--- a/themes/theme/layout/partials/head.ejs
+++ b/themes/theme/layout/partials/head.ejs
@@ -39,9 +39,8 @@
                                                                     <% }); %>
                                                                         <% } %>
 
-                                                                            <%# font preload - critical slices %>
-                                                                                <link rel="preload" href="<%- url_for('/fonts/latin-base.woff2') %>" as="font" type="font/woff2" crossorigin>
-                                                                                <link rel="preload" href="<%- url_for('/fonts/cjk-common.woff2') %>" as="font" type="font/woff2" crossorigin>
+            <%# font preload %>
+                <link rel="preload" href="<%- url_for('/fonts/TensentypeCode.woff2') %>" as="font" type="font/woff2" crossorigin>
 
                                                                     <%# javascript list %>
                                                                         <% if (theme.scripts !==undefined &&
diff --git a/themes/theme/source/css/font-slices.styl b/themes/theme/source/css/font-slices.styl
index 97b9b47b..3c90c548 100644
--- a/themes/theme/source/css/font-slices.styl
+++ b/themes/theme/source/css/font-slices.styl
@@ -1,47 +1,9 @@
-// FONT SLICES - GoogleSansCode 分段字体定义
-// 自动生成，包含 5 个 Unicode 范围切片
+// FONT - Tensentype Code
+// 单文件字体，替换原有的 GoogleSansCode 5 分片
 
-// Latin 基础字符集（ASCII + 基本拉丁 + 常用标点）
 @font-face
-  font-family 'GoogleSansCode'
+  font-family 'TensentypeCode'
   font-style normal
   font-weight 400
   font-display swap
-  src url('/fonts/latin-base.woff2') format('woff2')
-  unicode-range U+0000-00FF, U+0131, U+0152-0153, U+02C6, U+02DA, U+02DC, U+2000-206F
-
-// Latin 扩展（拉丁扩展 A/B + 货币符号 + 特殊字符）
-@font-face
-  font-family 'GoogleSansCode'
-  font-style normal
-  font-weight 400
-  font-display swap
-  src url('/fonts/latin-ext.woff2') format('woff2')
-  unicode-range U+0100-024F, U+0259, U+1E00-1EFF, U+2020, U+20A0-20AB, U+20AD-20CF, U+2113, U+2C60-2C7F, U+A720-A7FF
-
-// CJK 常用汉字（约 3500 字，覆盖 99% 中文内容）
-@font-face
-  font-family 'GoogleSansCode'
-  font-style normal
-  font-weight 400
-  font-display swap
-  src url('/fonts/cjk-common.woff2') format('woff2')
-  unicode-range U+4E00-62FF
-
-// CJK 扩展汉字（次常用汉字 + 扩展 A）
-@font-face
-  font-family 'GoogleSansCode'
-  font-style normal
-  font-weight 400
-  font-display swap
-  src url('/fonts/cjk-ext.woff2') format('woff2')
-  unicode-range U+6300-9FFF, U+3400-4DBF
-
-// 符号（CJK 标点 + 全角字符）
-@font-face
-  font-family 'GoogleSansCode'
-  font-style normal
-  font-weight 400
-  font-display swap
-  src url('/fonts/symbols.woff2') format('woff2')
-  unicode-range U+3000-303F, U+FF00-FFEF
+  src url('/fonts/TensentypeCode.woff2') format('woff2')
diff --git a/themes/theme/source/css/variable.styl b/themes/theme/source/css/variable.styl
index f8af5332..4deaed5d 100644
--- a/themes/theme/source/css/variable.styl
+++ b/themes/theme/source/css/variable.styl
@@ -18,7 +18,7 @@ $margin-s-2 = 4*$px
 $margin-s-1 = 2*$px
 $margin-s-0 = 1*$px
 
-$font-family = 'GoogleSansCode', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif
+$font-family = 'TensentypeCode', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif
 
 $font-weight-light = 300
 $font-weight-regular = 400
diff --git a/themes/theme/source/fonts/CarroisSong.ttf b/themes/theme/source/fonts/CarroisSong.ttf
deleted file mode 100644
index 9105c1a8..00000000
--- a/themes/theme/source/fonts/CarroisSong.ttf
+++ /dev/null
diff --git a/themes/theme/source/fonts/cjk-common.woff2 b/themes/theme/source/fonts/cjk-common.woff2
deleted file mode 100644
index 3140f04a..00000000
--- a/themes/theme/source/fonts/cjk-common.woff2
+++ /dev/null
diff --git a/themes/theme/source/fonts/cjk-ext.woff2 b/themes/theme/source/fonts/cjk-ext.woff2
deleted file mode 100644
index 6e1b840f..00000000
--- a/themes/theme/source/fonts/cjk-ext.woff2
+++ /dev/null
diff --git a/themes/theme/source/fonts/latin-base.woff2 b/themes/theme/source/fonts/latin-base.woff2
deleted file mode 100644
index 6e71c681..00000000
--- a/themes/theme/source/fonts/latin-base.woff2
+++ /dev/null
diff --git a/themes/theme/source/fonts/latin-ext.woff2 b/themes/theme/source/fonts/latin-ext.woff2
deleted file mode 100644
index 78abb265..00000000
--- a/themes/theme/source/fonts/latin-ext.woff2
+++ /dev/null
diff --git a/themes/theme/source/fonts/src/GoogleSansCode-Regular.ttf b/themes/theme/source/fonts/src/GoogleSansCode-Regular.ttf
deleted file mode 100644
index db4d27d3..00000000
--- a/themes/theme/source/fonts/src/GoogleSansCode-Regular.ttf
+++ /dev/null
diff --git a/themes/theme/source/fonts/symbols.woff2 b/themes/theme/source/fonts/symbols.woff2
deleted file mode 100644
index 59bc5d8d..00000000
--- a/themes/theme/source/fonts/symbols.woff2
+++ /dev/null