GraphQL Day(s) 2026 (#2367)

## Description

This PR adds GraphQL Day 2026 city pages (~~Amsterdam,~~ Paris,
Singapore, Melbourne, NYC).

Adds hero, speakers/testimonials, gallery, venue/map, FAQ, and shared
day layout/components.
Introduces schedule pages (list + session detail + OG images), local
media assets, and related content/data cleanup.

Closes #2362
Merge #2366 after this.

**Disclaimer:** I copy-pasted a lot of the code I wrote for other pages
on GraphQL.org. We might need a refactor if we do it a couple more
times.

## Screenshots

<img width="416" height="401" alt="image"
src="https://github.com/user-attachments/assets/6779ba0e-4364-476c-a6cf-3d284e1e4913"
/>
<img width="1497" height="886" alt="image"
src="https://github.com/user-attachments/assets/4e9feba8-2d45-4290-9d16-b32603de6a5e"
/>
<img width="1481" height="841" alt="image"
src="https://github.com/user-attachments/assets/4f8ff287-e690-4647-9ea7-15637dfb8cd2"
/>

---------

Co-authored-by: Martin Bonnin <martin@mbonnin.net>

Author: hasparus

.vscode/settings.json

@@ -18,5 +18,6 @@
   },
   "typescript.preferences.autoImportFileExcludePatterns": [
     "**/node_modules/lucide-react"
-  ]
+  ],
+  "tailwindCSS.experimental.configFile": "tailwind.config.ts"
 }