feat(article): 正文图片可放大——PhotoZoom 极简 viewer 双轨挂载

正文 .prose-reading/.prose-tech 图片单击唤起全屏 dialog：fit-
contain+滚轮光标锚点缩放 1-5x+拖拽（钳制数学与图库 v2 逐行同
源）+双击 1x↔2.5x+Esc/关闭/背景点击关（contain 内容盒几何判
定）；无 EXIF/caption/FLIP（纯图极简，按契约）；document
委托点击软导航后仍生效。

车道：op-artalk（专项 9/9：SVG 架构图唤起/矢量 2.46x 不栅格化/
拖拽钳制/双击回正/Esc/jpg/背景关/软导航）；收编验收四断言+E2E
34/34 全过

验证: 文章 SVG 点击唤起+滚轮放大（naturalWidth 960 矢量源）+Esc
      关闭实测；E2E 34/34

Spec: none (文章图放大，车道级交付)

Co-authored-by: GLM-5.3

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

@@ -1,6 +1,7 @@
 ---
 import type { CollectionEntry } from 'astro:content';
 import { getCollection, render } from 'astro:content';
+import PhotoZoom from '../../components/geek/PhotoZoom.astro';
 import BaseLayout from '../../layouts/BaseLayout.astro';
 import ArtalkComments from '../../components/ArtalkComments.astro';
 import { trackOf } from '../../content.config';
@@ -116,6 +117,7 @@ const toc = headings.filter((h) => h.depth === 2 || h.depth === 3);
   </nav>
 
   <ArtalkComments pageKey={`/archives/${entry.id}/`} pageTitle={entry.data.title} />
+  <PhotoZoom />
 </BaseLayout>
 
 <script>

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 PhotoZoom from '../../../components/geek/PhotoZoom.astro';
 import BaseLayout from '../../../layouts/BaseLayout.astro';
 import ArtalkComments from '../../../components/ArtalkComments.astro';
 import AiTranslatedBadge from '../../../components/AiTranslatedBadge.astro';
@@ -67,6 +68,7 @@ const minutes = Math.max(1, Math.ceil(words / 220));
     </nav>
     <ArtalkComments pageKey={`/archives/${entry.id}/`} pageTitle={entry.data.title} />
   </article>
+  <PhotoZoom />
 </BaseLayout>
 
 <style>