feat(pipeline): implement parliamentary embedding pipeline MVP

- Add 4 migration files: mp_votes, mp_metadata, svd_vectors, fused_embeddings
- Extend database.py with 5 new helper methods and table init
- Add pipeline/ package: extract_mp_votes, fetch_mp_metadata, text_pipeline,
  svd_pipeline (with Procrustes alignment), fusion
- Add full test suite (17 tests) covering all pipeline modules and migrations
- Fix Procrustes alignment bug: scipy scale is a norm value, not a multiplier
- Fix DuckDB date type handling in test assertions (datetime.date vs string)
- Remove duckdb.py shim; tests now run against real duckdb + scipy via uv

Ref: thoughts/shared/plans/2026-03-21-parliamentary-embedding-pipeline-plan.md

Dockerfile

@@ -0,0 +1,36 @@
+FROM python:3.13-slim
+
+# Install minimal system deps
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends build-essential curl ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+
+# Create non-root user for running the app
+RUN useradd -m -s /bin/bash app
+
+WORKDIR /home/app/app
+
+# Copy project files
+COPY . /home/app/app
+
+# Upgrade pip and install either pinned requirements or runtime defaults
+RUN python -m pip install --upgrade pip
+RUN if [ -f requirements.txt ]; then \
+      pip install -r requirements.txt; \
+    else \
+      pip install uv streamlit duckdb; \
+    fi
+
+# Fix permissions
+RUN chown -R app:app /home/app
+
+USER app
+ENV PYTHONPATH=/home/app/app
+
+EXPOSE 8501
+
+# Simple healthcheck that queries the Streamlit root
+HEALTHCHECK --interval=30s --timeout=3s --start-period=10s CMD curl -f http://localhost:8501/ || exit 1
+
+# Run the Streamlit app via uv as preferred in this project
+CMD ["uv", "run", "streamlit", "run", "app.py", "--server.port=8501", "--server.address=0.0.0.0"]