diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..369f4ef
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,2 @@
+# Ensure shell scripts always use LF so they run in Linux containers (e.g. Docker)
+*.sh text eol=lf
diff --git a/scripts/wait-for-api.sh b/scripts/wait-for-api.sh
index 2848cd4..285a4be 100755
--- a/scripts/wait-for-api.sh
+++ b/scripts/wait-for-api.sh
@@ -1,18 +1,21 @@
-#!/bin/bash
+#!/bin/sh
 # Wait for the API to be healthy before starting the frontend
 # This prevents the "Unable to Connect to API Server" error during startup
+# POSIX-compliant so it runs with /bin/sh (dash) in slim images
 
 API_URL="${INTERNAL_API_URL:-http://localhost:5055}"
-MAX_RETRIES=60  # 60 retries * 5 seconds = 5 minutes max wait
+MAX_RETRIES=60
 RETRY_INTERVAL=5
+i=0
 
 echo "Waiting for API to be ready at ${API_URL}/health..."
 
-for i in $(seq 1 $MAX_RETRIES); do
+while [ $i -lt $MAX_RETRIES ]; do
     if curl -s -f "${API_URL}/health" > /dev/null 2>&1; then
         echo "API is ready! Starting frontend..."
         exit 0
     fi
+    i=$((i + 1))
     echo "Attempt $i/$MAX_RETRIES: API not ready yet, waiting ${RETRY_INTERVAL}s..."
     sleep $RETRY_INTERVAL
 done