Fix 3 Code Review findings on FRE-4574

- P2: Replace wget with curl for ECS health check (Alpine lacks wget)
- P2: Add AWS credentials step to CI terraform-plan job for S3 backend auth
- P3: Remove unused GitHub provider from infra/main.tf

Co-Authored-By: Paperclip <noreply@paperclip.ing>

.github/workflows/deploy.yml

@@ -197,7 +197,7 @@ jobs:
           FAILED=0
           for service in api darkwatch spamshield voiceprint; do
             HTTP_CODE=$(curl -s -o /dev/null -w "%{http_code}" \
-              "http://${ALB_DNS}/health" || true)
+              "https://${ALB_DNS}/health" || true)
 
             if [ "$HTTP_CODE" = "200" ]; then
               echo "Health check passed: $service"