feat: Add Open Graph and Twitter meta tags for cloud distribution (#6571)

## Summary
- Add meta tags plugin for social media previews (Twitter, Facebook,
LinkedIn, etc.)
- Include SEO meta tags (title, description, keywords)
- Only applies to cloud distribution (`DISTRIBUTION === 'cloud'`)

## Changes
- Added Open Graph meta tags for better social media link previews
- Added Twitter Card meta tags for Twitter sharing
- Added SEO meta tags (title, description, keywords)
- Added `og-image.png` for preview image
- Meta tags only inject when `DISTRIBUTION === 'cloud'` to avoid
affecting other distributions

## Test plan
- [x] Build with `DISTRIBUTION=cloud pnpm build`
- [x] Verify meta tags appear in built HTML
- [ ] Test link sharing on Twitter, Facebook, Slack
- [ ] Verify meta tags don't appear in localhost/desktop builds

🤖 Generated with Claude Code

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6571-feat-Add-Open-Graph-and-Twitter-meta-tags-for-cloud-distribution-2a16d73d365081e58c73f6009513b2bb)
by [Unito](https://www.unito.io)

Author: viva-jinyi

public/assets/images/og-image.png

@@ -27,6 +27,15 @@ const VITE_REMOTE_DEV = process.env.VITE_REMOTE_DEV === 'true'
 const DISABLE_TEMPLATES_PROXY = process.env.DISABLE_TEMPLATES_PROXY === 'true'
 const GENERATE_SOURCEMAP = process.env.GENERATE_SOURCEMAP !== 'false'
 
+// Open Graph / Twitter Meta Tags Constants
+const VITE_OG_URL = 'https://cloud.comfy.org'
+const VITE_OG_TITLE =
+  'Comfy Cloud: Run ComfyUI online | Zero Setup, Powerful GPUs, Create anywhere'
+const VITE_OG_DESC =
+  'Bring your creative ideas to life with Comfy Cloud. Build and run your workflows to generate stunning images and videos instantly using powerful GPUs — all from your browser, no installation required.'
+const VITE_OG_IMAGE = `${VITE_OG_URL}/assets/images/og-image.png`
+const VITE_OG_KEYWORDS = 'ComfyUI, Comfy Cloud, ComfyUI online'
+
 // Auto-detect cloud mode from DEV_SERVER_COMFYUI_URL
 const DEV_SERVER_COMFYUI_ENV_URL = process.env.DEV_SERVER_COMFYUI_URL
 const IS_CLOUD_URL = DEV_SERVER_COMFYUI_ENV_URL?.includes('.comfy.org')
@@ -222,6 +231,90 @@ export default defineConfig({
       : [vue()]),
     tailwindcss(),
     comfyAPIPlugin(IS_DEV),
+    // Twitter/Open Graph meta tags plugin (cloud distribution only)
+    {
+      name: 'inject-twitter-meta',
+      transformIndexHtml(html) {
+        if (DISTRIBUTION !== 'cloud') return html
+
+        return {
+          html,
+          tags: [
+            // Basic SEO
+            { tag: 'title', children: VITE_OG_TITLE, injectTo: 'head' },
+            {
+              tag: 'meta',
+              attrs: { name: 'description', content: VITE_OG_DESC },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { name: 'keywords', content: VITE_OG_KEYWORDS },
+              injectTo: 'head'
+            },
+
+            // Twitter Card tags
+            {
+              tag: 'meta',
+              attrs: { name: 'twitter:card', content: 'summary_large_image' },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { name: 'twitter:title', content: VITE_OG_TITLE },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { name: 'twitter:description', content: VITE_OG_DESC },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { name: 'twitter:image', content: VITE_OG_IMAGE },
+              injectTo: 'head'
+            },
+
+            // Open Graph tags (Twitter fallback & other platforms)
+            {
+              tag: 'meta',
+              attrs: { property: 'og:title', content: VITE_OG_TITLE },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { property: 'og:description', content: VITE_OG_DESC },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { property: 'og:image', content: VITE_OG_IMAGE },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { property: 'og:url', content: VITE_OG_URL },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { property: 'og:type', content: 'website' },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { property: 'og:site_name', content: 'Comfy Cloud' },
+              injectTo: 'head'
+            },
+            {
+              tag: 'meta',
+              attrs: { property: 'og:locale', content: 'en_US' },
+              injectTo: 'head'
+            }
+          ]
+        }
+      }
+    },
     // Skip import-map generation for cloud builds to keep bundle small
     ...(DISTRIBUTION !== 'cloud'
       ? [