feat: update Dockerfile and requirements for ML dependencies; add base image build workflow

Dockerfile.base

@@ -0,0 +1,15 @@
+# Base image with all ML dependencies
+FROM python:3.13-bookworm
+
+# Install system dependencies
+RUN apt update && apt install -y libgl1 && rm -rf /var/lib/apt/lists/*
+
+# Copy and install base requirements (ML dependencies that rarely change)
+COPY requirements.base.txt .
+RUN pip install --no-cache-dir -r requirements.base.txt
+
+# Set working directory
+WORKDIR /app
+
+# This base image will be reused for all worker builds
+CMD ["python3", "-m", "fastapi", "run", "--host", "0.0.0.0", "--port", "8000"]