Add video card insert feature + MkDocs video hydration + fixes

- New video card block for GrapesJS landing pages, email templates,
  MkDocs export, and documentation editor Insert dropdown
- Shared HTML generators in admin/src/utils/videoCardHtml.ts
- MkDocs video-player.js hydrates .video-card-block elements:
  thumbnail fix via MEDIA_API_URL, click-to-play inline, Gallery link
- Media API CORS: auto-add MkDocs + docs subdomain origins
- env_config_hook.py: smart Docker hostname detection, ADMIN_PORT
  resolution, pass env vars to MkDocs container
- Gallery URL uses /gallery?expanded=ID format
- VideoPickerModal: fix double /api prefix and Docker hostname thumbs
- Seed: default-video-card PageBlock
- Remove V1 legacy code (influence/, map/)

Bunker Admin

api/prisma/seed.ts

@@ -218,6 +218,27 @@ async function main() {
         showReactions: true,
       },
     },
+    {
+      id: 'default-video-card',
+      type: 'video-card',
+      label: 'Video Card',
+      category: 'Media',
+      sortOrder: 8,
+      schema: {
+        videoId: { type: 'number', label: 'Video ID', required: true },
+        title: { type: 'string', label: 'Title' },
+        durationSeconds: { type: 'number', label: 'Duration (seconds)', default: 0 },
+        quality: { type: 'string', label: 'Quality (e.g. 1080p)' },
+        viewCount: { type: 'number', label: 'View Count', default: 0 },
+      },
+      defaults: {
+        videoId: null,
+        title: '',
+        durationSeconds: 0,
+        quality: '',
+        viewCount: 0,
+      },
+    },
   ];
 
   for (const block of defaultBlocks) {