style(site): 在顶部导航栏 GitHub 图标旁新增双语『开源』标识

- 参照极客产品风格，将 Navbar 右侧 GitHub 简易图标升级为包含『开源』/『Open Source』文本的胶囊标签；
- 支持中英文双语对齐与响应式 Mobile 适配。

apps/site/src/components/navbar/navbar.astro

@@ -102,10 +102,11 @@ const menuitems = [
             href="https://github.com/tianma-if/edgeever"
             target="_blank"
             rel="noopener"
-            class="flex h-10 w-10 shrink-0 items-center justify-center rounded-lg border border-slate-200 bg-white text-gray-600 transition hover:border-slate-300 hover:text-gray-900"
+            class="inline-flex items-center gap-1.5 px-3 py-1.5 text-xs font-semibold text-slate-700 bg-white border border-slate-200 rounded-full"
             aria-label="GitHub"
           >
-            <Icon class="h-5 w-5" name="bx:bxl-github" />
+            <Icon class="h-4 w-4 text-slate-800" name="bx:bxl-github" />
+            <span>{copy.openSource}</span>
           </a>
           <LanguageSwitcher pathname={Astro.url.pathname} compact />
         </div>
@@ -118,10 +119,11 @@ const menuitems = [
           href="https://github.com/tianma-if/edgeever"
           target="_blank"
           rel="noopener"
-          class="flex h-10 w-10 shrink-0 items-center justify-center rounded-lg border border-slate-200 bg-white text-gray-600 transition hover:border-slate-300 hover:text-gray-900"
+          class="inline-flex items-center gap-1.5 px-3 py-1.5 text-xs font-semibold text-slate-700 hover:text-slate-900 bg-white hover:bg-slate-50 border border-slate-200 hover:border-slate-300 rounded-full transition-all duration-200 shadow-2xs"
           aria-label="GitHub"
         >
-          <Icon class="h-5 w-5" name="bx:bxl-github" />
+          <Icon class="h-4 w-4 text-slate-800" name="bx:bxl-github" />
+          <span>{copy.openSource}</span>
         </a>
       </div>
     </div>

apps/site/src/i18n.ts

@@ -53,6 +53,7 @@ export const siteCopy = {
       tagMigration: "迁移教程",
       tagMcp: "AI 协同 (MCP)",
       tagSelfHosted: "部署自托管",
+      openSource: "开源",
     },
     hero: {
       slogan: siteTaglines["zh-CN"],
@@ -305,6 +306,7 @@ export const siteCopy = {
       tagMigration: "Migration",
       tagMcp: "AI & MCP",
       tagSelfHosted: "Deployment",
+      openSource: "Open Source",
     },
     hero: {
       slogan: siteTaglines["en-US"],