feat(cms): 内容管理闭环——站点单例三件套+文章视频字段

- A 站点文案单例：content/site/{home,about,opensource}.yaml +
  src/lib/site-content.ts 访问层（字段级回落默认，默认值=原文案逐字
  一致，零回归）；接线主页 tagline（en 首页新增该块）、关于页 intro、
  开源页叙述三段 + PINNED 参数化（projects.ts: loadProjects(pinned)
  /orderPinned，PINNED_DEFAULT 仅缺省兜底）
- loader 语义修正（返工如实入档）：Astro 7 的 file() 把 YAML 顶层对象
  按 Object.entries 拆成多条目（id=key、data=value），单例字段必炸
  schema；改 glob 精确到单文件 = 真单例语义，data 即文件根对象，
  Sveltia 可编辑根字段零嵌套（比包 main: 层的方案后台体验更好）
- B 文章媒体：posts +video/+poster；Sveltia file 字段
  （media_folder=public/media、public_folder=/media、hint ≤50MB）；
  正文后渲染 video controls preload=metadata playsinline，无则不渲染；
  图片链路核对本已一致（./assets 走 Astro 管线）；链接 markdown 原生
- docs/写作指南.md 补「后台上传」节（三类媒体 + 三单例操作 + 体积纪律）

Sveltia 集合：posts / moments / photos / site_pages（三单例）

车道：op-gitea（实测 tagline 改 yaml 产物联动、置空回落默认、pinned
改名排序变、视频临时件渲染全对、构建绿 + lint 45 页 0/0/0）；收编
复验：构建 44 页 + E2E 37/37 + 三 yaml 扁平键就位

验证: pnpm astro build 44 页 exit 0；E2E 37/37 PASS；content-lint
      0/0/0；播放器/单例/置顶 playwright 实测全过

Spec: none (内容管理闭环，车道级交付)

Co-authored-by: GLM-5.3

src/pages/en/archives/[...slug].astro

@@ -2,6 +2,7 @@
 // /en/archives/{slug}：英文版文章页——postsEn 优先；缺译回退 zh 正文 + 醒目标注
 import type { CollectionEntry } from 'astro:content';
 import { getCollection, render } from 'astro:content';
+import LinkCardStyles from '../../../components/geek/LinkCardStyles.astro';
 import PhotoZoom from '../../../components/geek/PhotoZoom.astro';
 import BaseLayout from '../../../layouts/BaseLayout.astro';
 import ArtalkComments from '../../../components/ArtalkComments.astro';
@@ -61,6 +62,14 @@ const minutes = Math.max(1, Math.ceil(words / 220));
     <AiTranslatedBadge />
     <div class={isReading ? 'prose-reading' : 'prose-tech'}>
       <Content />
+      {entry.data.video && (
+        <figure class="post-video">
+          <video controls preload="metadata" playsinline poster={entry.data.poster}>
+            <source src={entry.data.video} />
+            Your browser cannot play embedded video — <a href={entry.data.video}>download it instead</a>.
+          </video>
+        </figure>
+      )}
     </div>
     <nav class="pn">
       {prev && <a class="pn-item" href={`/en/archives/${prev.id}/`}>← {t('prev_post', 'en')} · {prev.data.title}</a>}
@@ -68,6 +77,7 @@ const minutes = Math.max(1, Math.ceil(words / 220));
     </nav>
     <ArtalkComments pageKey={`/archives/${entry.id}/`} pageTitle={entry.data.title} />
   </article>
+  <LinkCardStyles />
   <PhotoZoom />
 </BaseLayout>
 
@@ -116,6 +126,17 @@ const minutes = Math.max(1, Math.ceil(words / 220));
   }
 
   /* ---- T6 reading paper card (§6-2) ---- */
+  /* 文章附视频：与 zh 版同构（cms 车道 B） */
+  .post-video {
+    margin: var(--space-4) 0 0;
+  }
+  .post-video video {
+    width: 100%;
+    height: auto;
+    border-radius: 10px;
+    background: #000;
+    display: block;
+  }
   .prose-reading {
     border: 1px solid var(--paper-line);
     border-radius: 12px;

src/pages/en/index.astro

@@ -8,6 +8,7 @@ import PostList from '../../components/PostList.astro';
 import ProjectWall from '../../components/geek/ProjectWall.astro';
 import Heatmap from '../../components/geek/Heatmap.astro';
 import { t } from '../../i18n/ui';
+import { homeTagline } from '../../lib/site-content';
 
 const posts = (await getCollection('posts', ({ data }) => !data.draft && !data.tags.includes('hidden'))).sort(
   (a, b) => b.data.pubDate.getTime() - a.data.pubDate.getTime(),
@@ -17,10 +18,13 @@ const enTitle = Object.fromEntries(
   (await getCollection('postsEn')).map((e) => [e.id, e.data.title]),
 );
 const photos = (await getCollection('photos')).slice(0, 4);
+// 身份语与 zh 版同源（content/site/home.yaml 的 en 字段），缺值回落默认
+const tagline = await homeTagline('en');
 ---
 
 <BaseLayout title="wait4x" description="wait4x's blog: reading · code · photography">
   <IdCard>
+    <p class="tagline">{tagline}</p>
     <div class="socials">
       <a
         class="tap social"
@@ -103,6 +107,12 @@ const photos = (await getCollection('photos')).slice(0, 4);
 </BaseLayout>
 
 <style>
+  .tagline {
+    font-size: 14px;
+    color: var(--ink-3);
+    margin-top: 4px;
+    letter-spacing: 0.01em;
+  }
   .socials {
     display: flex;
     align-items: center;

src/pages/en/opensource.astro

@@ -3,15 +3,18 @@ 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';
+
+const copy = await openSourceCopy('en');
 ---
 <BaseLayout title="Open Source · wait4x" description="My open-source activity: repos, contributions, and this site's source">
   <h1 class="page-title">Open Source</h1>
-  <p class="blurb">This site is itself open source: <a class="link" href="https://git.wait4x.online/wait4x/blog">git.wait4x.online/wait4x/blog</a> — the Astro SSG, dual-writing workflow, and the full build &amp; deploy pipeline live in the repo. Below are all my public repositories on self-hosted gitea and GitHub, plus contributions from the past year.</p>
+  <p class="blurb">{copy.blurb}<a class="link" href={copy.repoUrl}>{copy.repoLabel}</a>{copy.blurbAfter}</p>
   <Heatmap labels={{
     title: t('heatmap_title', 'en'), summary: t('heatmap_summary', 'en'),
     less: t('heatmap_less', 'en'), more: t('heatmap_more', 'en'), note: t('heatmap_note', 'en'),
   }} />
-  <ProjectWall limit={99} locale="en" />
+  <ProjectWall limit={99} locale="en" pinned={copy.pinned} />
 </BaseLayout>
 
 <style>