Add generated SQL columns for graph properties

AGE keeps all properties in one agtype column and its Cypher writes fire
no triggers, so the bridge periodically calls a stored procedure that adds
a stored generated text column for every new property key. Only label
tables with inserts or updates since the previous run are scanned.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Dockerfile

@@ -70,6 +70,8 @@ ENV PEO4C_DEFAULT_GRAPH=neo4j \
     PEO4C_BOLT_PORT=7687 \
     PEO4C_PG_HOST=127.0.0.1 \
     PEO4C_PG_PORT=5432 \
+    PEO4C_PROPERTY_COLUMNS=true \
+    PEO4C_PROPERTY_COLUMNS_INTERVAL=5 \
     PEO4C_PGADMIN=true \
     PEO4C_PGADMIN_PORT=5050 \
     CONFIG_DISTRO_FILE_PATH=/opt/peo4c/pgadmin/config_distro.py