Fix: docker build

Dockerfile

@@ -6,8 +6,16 @@ WORKDIR /app
 # Install build dependencies
 RUN apt-get update && apt-get install -y --no-install-recommends \
     build-essential \
+    curl \
+    pkg-config \
+    libssl-dev \
+    && curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y \
+    && . "$HOME/.cargo/env" \
+    && rustup default stable \
     && rm -rf /var/lib/apt/lists/*
 
+ENV PATH="/root/.cargo/bin:${PATH}"
+
 # Copy only requirements files first to leverage Docker cache
 COPY requirements.txt .
 COPY lightrag/api/requirements.txt ./lightrag/api/