Move peo package to a different spot to prepare it for PyPI

Dockerfile

@@ -5,8 +5,8 @@
 #
 # Stage 1 builds the neo4j-browser static frontend from source.
 # Stage 2 is the Apache AGE image (PostgreSQL with the AGE extension) plus the
-# peo bridge, which speaks the Bolt protocol to the browser and translates
-# Cypher into AGE `cypher()` calls, and pgAdmin as a SQL interface.
+# peo Python package, which speaks the Bolt protocol to the browser and
+# translates Cypher into AGE `cypher()` calls, and pgAdmin as a SQL interface.
 
 ARG AGE_IMAGE=docker.io/apache/age:release_PG18_1.8.0
 # Commit of apache/age's release/PG18/1.8.0 branch, for AGE's LICENSE and NOTICE.
@@ -59,7 +59,12 @@ ADD https://raw.githubusercontent.com/apache/age/${AGE_SOURCE_REF}/LICENSE \
     /usr/share/doc/peo/apache-age/
 
 COPY --from=browser /src/dist /opt/peo/browser
-COPY bridge /opt/peo/bridge
+# peo itself, using Debian's psycopg.
+COPY pyproject.toml README.md LICENSE /tmp/peo/
+COPY peo /tmp/peo/peo
+RUN python3 -m venv --system-site-packages /opt/peo/venv \
+    && /opt/peo/venv/bin/pip install --no-cache-dir --no-deps /tmp/peo \
+    && rm -r /tmp/peo
 COPY docker/initdb/ /docker-entrypoint-initdb.d/
 COPY docker/pgadmin/config_distro.py /opt/peo/pgadmin/config_distro.py
 COPY docker/peo-entrypoint.sh /usr/local/bin/peo-entrypoint.sh