fix: resolve two build errors blocking deploy

1. Replace stale supabase import with api in sweet-corn-box page —
   src/lib/supabase.ts was removed when migrating to better-auth.

2. Stub bun-sqlite-dialect from @better-auth/kysely-adapter via webpack
   alias — it imports DEFAULT_MIGRATION_TABLE which doesn't exist in
   kysely 0.29.x and is never used (we use PostgresDialect, not bun-sqlite).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

next.config.ts

@@ -121,6 +121,18 @@ const nextConfig: NextConfig = {
     ];
   },
 
+  // Stub out bun-sqlite dialect bundled inside @better-auth/kysely-adapter.
+  // It imports kysely migration symbols that don't exist in kysely 0.29.x and
+  // is never used at runtime (we use PostgresDialect). Aliasing to false
+  // makes webpack treat it as an empty module.
+  webpack(config) {
+    config.resolve.alias = {
+      ...config.resolve.alias,
+      "@better-auth/kysely-adapter/dist/bun-sqlite-dialect-DzNwOpKv.mjs": false,
+    };
+    return config;
+  },
+
   // Experimental features
   experimental: {
     // Enable optimizePackageImports for better bundle size