fix: use relative paths for SVG imports to pass Vite fs.allow during build

Slidev converts <img src> to ES imports during build. Absolute paths like
/pipeline.svg resolve to the filesystem root, failing the slidev:slide-import-guard
plugin. Changed to relative ../public/ paths so imports resolve within the project.

decks/gen2D/pages/prompt-agent.md

@@ -15,5 +15,5 @@ Eino Chain 驱动的智能提示词生成
 </Item>
 
 <div class="flex justify-center">
-  <img src="/prompt-agent.svg" class="w-full max-h-[160px] object-contain" />
+  <img src="../public/prompt-agent.svg" class="w-full max-h-[160px] object-contain" />
 </div>