Remove unused API file and update gitignore

- Delete src/pages/api/filaments.ts that was causing build failure
- Add .vite/ to gitignore

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.gitignore

@@ -10,6 +10,9 @@ coverage/
 dist/
 build/
 
+# Vite
+.vite/
+
 # Misc
 .DS_Store
 .env