feat(docker): add container detection warning

- Check for existing container ports (Streamlit/NoVNC)
- Add helpful warning with docker commands
- Auto-retry for commonly conflicting ports (VNC/HTTP)
- Continue execution to allow multiple instances

Related to anthropics#147

computer-use-demo/_.sh

@@ -1,3 +1,52 @@
+#!/bin/bash
+
+# Function to check if a port is available
+check_port() {
+    local port=$1
+    if command -v lsof >/dev/null 2>&1; then
+        lsof -i :"$port" >/dev/null 2>&1
+        return $?
+    else
+        # Fallback to nc if lsof is not available
+        nc -z localhost "$port" >/dev/null 2>&1
+        return $?
+    fi
+}
+
+# Function to find an available port
+find_available_port() {
+    local base_port=$1
+    local port=$base_port
+    local max_attempts=9
+
+    for i in $(seq 0 $max_attempts); do
+        if ! check_port "$port"; then
+            echo "$port"
+            return 0
+        fi
+        port=$((base_port + i + 1))
+    done
+
+    echo "No available ports found between $base_port and $((base_port + max_attempts))" >&2
+    exit 1
+}
+
+# Check if likely another container is running
+if check_port 8501 || check_port 6080; then
+    echo "⚠️  Warning: Ports 8501 or 6080 are in use. You might have another container running."
+    echo "   You may want to run 'docker ps' to check and 'docker stop <container-id>' if needed."
+    echo "   Continuing in 3 seconds..."
+    sleep 3
+fi
+
+# Find available ports for commonly conflicting services
+VNC_PORT=$(find_available_port 5900)
+HTTP_PORT=$(find_available_port 8080)
+STREAMLIT_PORT=8501
+NOVNC_PORT=6080
+
+echo "Using ports: VNC=$VNC_PORT, HTTP=$HTTP_PORT, STREAMLIT=$STREAMLIT_PORT, NOVNC=$NOVNC_PORT"
+
 docker run \
     -e GITHUB_TOKEN=$GITHUB_TOKEN \
     -e ANTHROPIC_API_KEY=$ANTHROPIC_API_KEY \
@@ -6,8 +55,8 @@ docker run \
     -e AWS_REGION=$AWS_REGION \
     -e PROVIDER=bedrock \
     -v $HOME/.anthropic:/home/computeruse/.anthropic \
-    -p 5900:5900 \
-    -p 8501:8501 \
-    -p 6080:6080 \
-    -p 8080:8080 \
+    -p $VNC_PORT:5900 \
+    -p $STREAMLIT_PORT:8501 \
+    -p $NOVNC_PORT:6080 \
+    -p $HTTP_PORT:8080 \
     -it ghcr.io/anthropics/anthropic-quickstarts:computer-use-demo-latest