feat(opensource): README 开篇接线+缓存入仓（收编遗漏补齐）

zh 开源页补收编（此前只提交了 en）：githubReadmeMarkdown + renderMarkdown
接线，content/.github-readme.md 缓存入仓（现状 intro_from=off，开启即生效）。

验证: 构建 48 页 exit 0

Spec: none (收编遗漏补齐)

Co-authored-by: GLM-5.3

src/pages/opensource.astro

@@ -3,23 +3,36 @@ import ProjectWall from '../components/geek/ProjectWall.astro';
 import Heatmap from '../components/geek/Heatmap.astro';
 import BaseLayout from '../layouts/BaseLayout.astro';
 import { t } from '../i18n/ui';
-import { openSourceCopy } from '../lib/site-content';
+import { githubReadmeMarkdown, openSourceCopy, openSourceOptions, renderMarkdown } from '../lib/site-content';
 
-// 叙述文案 + 置顶名单均改由 content/site/opensource.yaml 供给（后台可改）
+// 叙述文案 + 置顶名单 + 项目墙选项均改由 content/site/opensource.yaml 供给（后台可改）
 const copy = await openSourceCopy('zh');
+const options = await openSourceOptions();
+// 开篇来源：github-readme → 构建期取 profile 仓 README（缓存 content/.github-readme.md，失败回落 yaml blurb）
+const readmeMd = options.introFrom === 'github-readme' ? await githubReadmeMarkdown() : null;
+const readmeHtml = readmeMd ? await renderMarkdown(readmeMd) : null;
 ---
 <BaseLayout title="开源 · wait4x" description="我的开源活动：仓库、贡献与本站源码">
   <h1 class="page-title">开源<span class="count mono">Open Source</span></h1>
-  <p class="blurb">{copy.blurb}<a class="link" href={copy.repoUrl}>{copy.repoLabel}</a>{copy.blurbAfter}</p>
+  {readmeHtml ? (
+    <div class="blurb readme-intro" set:html={readmeHtml} />
+  ) : (
+    <p class="blurb">{copy.blurb}<a class="link" href={copy.repoUrl}>{copy.repoLabel}</a>{copy.blurbAfter}</p>
+  )}
   <Heatmap labels={{
     title: t('heatmap_title', 'zh'), summary: t('heatmap_summary', 'zh'),
     less: t('heatmap_less', 'zh'), more: t('heatmap_more', 'zh'), note: t('heatmap_note', 'zh'),
   }} />
-  <ProjectWall limit={99} pinned={copy.pinned} />
+  <ProjectWall limit={99} pinned={copy.pinned} options={options} />
 </BaseLayout>
 
 <style>
   .page-title { font-size: var(--text-h1); color: var(--ink-1); display: flex; align-items: baseline; gap: var(--space-3); }
   .count { font-size: 13px; color: var(--ink-4); }
+  .readme-intro :global(p) { margin-block: 0 var(--space-2); }
+  .readme-intro :global(ul) { margin-block: var(--space-1) var(--space-2); padding-left: 1.2em; list-style: disc; }
+  .readme-intro :global(h2), .readme-intro :global(h3) { font-size: 16px; margin: var(--space-3) 0 var(--space-1); }
+  .readme-intro :global(img) { max-width: 100%; height: auto; border-radius: 8px; }
+  .readme-intro :global(a) { color: var(--accent); }
   .blurb { margin-top: var(--space-3); margin-bottom: var(--space-5); font-size: 15px; color: var(--ink-2); line-height: 1.7; max-width: 640px; }
 </style>