ci: add QEMU/Buildx for arm64 cross-platform build

Author: chetanr25

.github/workflows/backend-ci-cd.yml

@@ -68,6 +68,12 @@ jobs:
       - name: Checkout Code
         uses: actions/checkout@v4
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
       - name: Configure AWS Credentials
         uses: aws-actions/configure-aws-credentials@v4
         with:
@@ -88,11 +94,13 @@ jobs:
           # Build a docker container and push it to ECR
           # Using --platform linux/arm64 for Lambda compatibility
           cd backend
-          docker build --platform linux/arm64 -t $ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG .
-          docker push $ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG
+          docker buildx build --platform linux/arm64 -t $ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG --push .
 
       - name: Update Lambda Function
+        env:
+          ECR_REGISTRY: ${{ steps.login-ecr.outputs.registry }}
+          ECR_REPOSITORY: ${{ secrets.ECR_REPOSITORY }}
         run: |
           aws lambda update-function-code \
             --function-name ${{ secrets.LAMBDA_FUNCTION_NAME }} \
-            --image-uri ${{ steps.login-ecr.outputs.registry }}/${{ secrets.ECR_REPOSITORY }}:latest
+            --image-uri $ECR_REGISTRY/$ECR_REPOSITORY:latest

backend/app/ai/email_tools.py

@@ -405,7 +405,7 @@ def send_detailed_analysis_email(
         "total_matches": len(colleges),
         "high_chance_count": high_chance,
         "branches_count": len(branches),
-        "colleges": colleges[:15],  # Top 15
+        "colleges": colleges[:50],
         "branch_distribution": branch_distribution or [],
         "generation_date": datetime.now(),
         "chat_url": _get_chat_url(session_id),