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/Dockerfile

@@ -6,10 +6,9 @@
 FROM apache/superset:6.1.0@sha256:16b50bbef6648912a79e3293d418fefa743ce555d36c5af6b85d859119ed7f88
 
 USER root
-# The 6.1.0 image ships neither an OAuth client nor the Postgres and Trino
-# drivers.
+# The 6.1.0 image ships neither an OAuth client nor the Postgres driver.
 RUN uv pip install --no-cache --python /app/.venv/bin/python \
-      authlib==1.9.1 psycopg2-binary==2.9.13 "trino[sqlalchemy]==0.340.0"
+      authlib==1.9.1 psycopg2-binary==2.9.13
 
 COPY --from=insights --chown=superset:superset superset_config.py petrolyst_security.py /app/pythonpath/
 COPY --from=insights --chown=superset:superset roles/ /app/petrolyst-roles/