feat: add base image Dockerfile with curl, poppler-utils, imagemagick

PR 1 of 5 — minimal base image on debian:13.4 with:
- uv (from astral-sh/uv:latest)
- curl
- poppler-utils (pdftotext, pdfinfo, pdftoppm)
- imagemagick (convert, identify)

Verified all tools report version on build.

ai/Dockerfile

@@ -0,0 +1,23 @@
+FROM debian:13.4
+
+# Install uv (Python package manager), curl, poppler-utils, and imagemagick
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+        curl \
+        poppler-utils \
+        imagemagick && \
+    rm -rf /var/lib/apt/lists/*
+
+# Install uv if not already present (debian:13.4 doesn't ship it)
+COPY --from=ghcr.io/astral-sh/uv:latest /usr/local/bin/uv /usr/local/bin/uv
+RUN uv --version
+
+# Verify all expected tools are available
+RUN curl --version && \
+    pdftotext -v 2>&1 | head -1 && \
+    pdfinfo -v 2>&1 | head -1 && \
+    pdftoppm -v 2>&1 | head -1 && \
+    convert --version | head -1 && \
+    identify --version | head -1
+
+CMD ["/bin/bash"]