feat: store node logo/favicon in postgres instead of S3

- Add logoData and faviconData columns to nodes table
- Create /api/admin/node/upload endpoint for direct DB storage
- Create /api/node/logo and /api/node/favicon endpoints to serve images
- Update admin page to use new upload endpoint
- Remove dependency on admin's personal S3 storage for node assets

src/lib/contexts/AuthContext.tsx

@@ -7,6 +7,7 @@ export interface User {
     id: string;
     handle: string;
     displayName: string;
+    email?: string;
     avatarUrl?: string;
     did?: string;
     publicKey?: string;