fixed arm build, reduced image size

Dockerfile

@@ -1,16 +1,35 @@
-FROM python:3.11-slim
+# Build stage - compile dependencies
+FROM python:3.11-slim AS builder
 
 WORKDIR /app
 
-# Install system dependencies
+# Install build dependencies (only in this stage)
 RUN apt-get update && apt-get install -y --no-install-recommends \
     gcc \
+    libssl-dev \
+    libffi-dev \
+    python3-dev \
+    cargo \
+    rustc \
     && rm -rf /var/lib/apt/lists/*
 
 # Install Python dependencies
 COPY requirements.txt .
 RUN pip install --no-cache-dir --upgrade pip && \
-    pip install --no-cache-dir -r requirements.txt
+    pip install --no-cache-dir --prefix=/install -r requirements.txt
+
+# Final stage - minimal runtime image
+FROM python:3.11-slim
+
+WORKDIR /app
+
+# Install only runtime dependencies (not build tools!)
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    libssl3 \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy installed Python packages from builder
+COPY --from=builder /install /usr/local
 
 # Copy application files
 COPY backend ./backend