Remove Trino: Superset reads fuel-db directly as fuel_ro (PD-14)

trino/ deleted; the role trino_ro becomes fuel_ro, its password read from a
secret file at connect time; dashboards' SQL and column list for PostgreSQL;
the Compose project is renamed petrolyst, with volumes pinned to their old
names. AGENTS.md points to the architecture context. Not deployed: the next
deploy needs README's one-time steps first.

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

stacks/fuel-monitoring/superset/init.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # superset-init: migrate the metadata database, sync roles and permissions, and
-# register the Trino connection. It is copied into the Superset image, so a
+# register the connection to fuel-db. It is copied into the Superset image, so a
 # change here changes the image tag; deploy/deploy.sh runs it on a fresh install
 # and whenever that tag changes. Every step is idempotent. Unlike the
 # upstream docker-init.sh it never creates a local admin: users come from
@@ -9,6 +9,25 @@ set -euo pipefail
 
 superset db upgrade
 superset init
+
+# Trino was removed on 29 Oct 2026. An instance still holding its connection
+# "Fuel (Trino)" gets it renamed, so its datasets and dashboards keep their ids;
+# the next step points it at fuel-db. Drop this once no instance has it.
+/app/.venv/bin/python - <<'PY'
+from superset.app import create_app
+
+with create_app().app_context():
+    from superset import db
+    from superset.models.core import Database
+
+    old = db.session.query(Database).filter_by(database_name="Fuel (Trino)").one_or_none()
+    if old and not db.session.query(Database).filter_by(database_name="Fuel").count():
+        old.database_name = "Fuel"
+        db.session.commit()
+        print('renamed the connection "Fuel (Trino)" to "Fuel"')
+PY
+
+# No password here: superset_config.py reads it from /run/secrets at connect time.
 superset set-database-uri \
-  --database_name "Fuel (Trino)" \
-  --uri "trino://superset@trino:8080/fuel"
+  --database_name "Fuel" \
+  --uri "postgresql+psycopg2://fuel_ro@fuel-db:5432/fuel"