fix(cv): isolate document parsing

Run untrusted document decoders in a secret-free, resource-bounded child process and terminate its process tree on deadline. Harden the production container and enforce parser and lint gates in CI.

tools/summarizer/Dockerfile

@@ -2,8 +2,11 @@ FROM python:3.12.10-slim-bookworm
 ENV PIP_NO_CACHE_DIR=1 \
     PIP_DISABLE_PIP_VERSION_CHECK=1 \
     PYTHONUNBUFFERED=1 \
+    PYTHONDONTWRITEBYTECODE=1 \
     TRANSFORMERS_NO_TF=1 \
-    HF_HUB_DISABLE_TELEMETRY=1
+    HF_HUB_DISABLE_TELEMETRY=1 \
+    HF_HOME=/home/app/.cache/huggingface \
+    PARSER_TEMP_ROOT=/tmp
 WORKDIR /app
 RUN apt-get update \
     && apt-get install -y --no-install-recommends tesseract-ocr tesseract-ocr-eng \
@@ -12,5 +15,10 @@ COPY requirements-linux.lock ./
 RUN python -m pip install --upgrade pip setuptools wheel \
     && python -m pip install --require-hashes --extra-index-url https://download.pytorch.org/whl/cpu -r requirements-linux.lock
 COPY . .
+RUN groupadd --system app \
+    && useradd --system --gid app --home-dir /home/app --create-home app \
+    && mkdir -p /home/app/.cache/huggingface \
+    && chown -R app:app /app /home/app
+USER app
 EXPOSE 8001
 CMD ["uvicorn", "app:app", "--host", "0.0.0.0", "--port", "8001"]