feat(ui): add wedding theme styles and layout components

* Introduced wedding-themed CSS variables for styling.
* Created layout component for the wedding site with navigation and countdown.
* Added RSVP and photo upload pages with form handling.
* Implemented QR code page for wedding site access.
* Configured TypeScript and Vite for the project.
* Added robots.txt for search engine crawling.

ui/.gitignore

@@ -0,0 +1,23 @@
+node_modules
+
+# Output
+.output
+.vercel
+.netlify
+.wrangler
+/.svelte-kit
+/build
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Env
+.env
+.env.*
+!.env.example
+!.env.test
+
+# Vite
+vite.config.js.timestamp-*
+vite.config.ts.timestamp-*