fix: add node and curl dependencies to backend docker image

backend/Dockerfile

@@ -2,6 +2,13 @@ FROM python:3.10-slim
 
 WORKDIR /app
 
+# Install Node.js (for AIS WebSocket proxy) and curl (for network fallback)
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    curl \
+    && curl -fsSL https://deb.nodesource.com/setup_20.x | bash - \
+    && apt-get install -y --no-install-recommends nodejs \
+    && rm -rf /var/lib/apt/lists/*
+
 # Install dependencies
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt