refactor(auth): consolidate remaining direct Amplify calls to use auth helpers

Replace direct runWithAmplifyServerContext/fetchAuthSession calls in
cognito-token route with tryGetAuthSession(), and replace manual
getAuthSession + prisma.user.findUnique in authActionClient with
getSessionWithUser().

This eliminates duplicate auth code paths that were missed in the
initial refactor, ensuring all authentication flows go through the
centralized auth.ts helpers. The change also benefits from cache()
memoization in getSessionWithUser() to avoid redundant DB lookups
within the same request.

Author: konokenj

webapp/src/app/api/cognito-token/route.ts

@@ -1,21 +1,15 @@
 import { NextResponse } from 'next/server';
-import { cookies } from 'next/headers';
-import { fetchAuthSession } from 'aws-amplify/auth/server';
-import { runWithAmplifyServerContext } from '@/lib/amplifyServerUtils';
+import { tryGetAuthSession } from '@/lib/auth';
 
 export async function GET() {
   try {
-    const session = await runWithAmplifyServerContext({
-      nextServerContext: { cookies },
-      operation: (contextSpec) => fetchAuthSession(contextSpec),
-    });
-
-    if (session.tokens?.accessToken == null) {
+    const session = await tryGetAuthSession();
+    if (!session) {
       return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
     }
 
     return NextResponse.json({
-      accessToken: session.tokens.accessToken.toString(),
+      accessToken: session.accessToken,
     });
   } catch (error) {
     console.error('Error fetching Cognito token:', error);

webapp/src/lib/safe-action.ts

@@ -1,5 +1,4 @@
-import { getAuthSession } from '@/lib/auth';
-import { prisma } from '@/lib/prisma';
+import { getSessionWithUser } from '@/lib/auth';
 import { createSafeActionClient, DEFAULT_SERVER_ERROR_MESSAGE } from 'next-safe-action';
 
 export class MyCustomError extends Error {
@@ -26,17 +25,6 @@ const actionClient = createSafeActionClient({
 });
 
 export const authActionClient = actionClient.use(async ({ next }) => {
-  const { userId } = await getAuthSession();
-
-  const user = await prisma.user.findUnique({
-    where: {
-      id: userId,
-    },
-  });
-
-  if (user == null) {
-    throw new Error('user not found');
-  }
-
+  const { user } = await getSessionWithUser();
   return next({ ctx: { userId: user.id } });
 });