Fix OAuth callback: remove from middleware, fix redirect URLs

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

middleware.ts

@@ -38,6 +38,7 @@ export async function middleware(request: NextRequest) {
 export const config = {
   matcher: [
     // Only run middleware on specific routes that need auth handling
+    // Note: /auth/callback is excluded - it handles its own auth flow
     '/dashboard/:path*',
     '/settings/:path*',
     '/subscription/:path*',
@@ -45,6 +46,5 @@ export const config = {
     '/login/',
     '/register',
     '/register/',
-    '/auth/:path*',
   ],
 }