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/fuel-db/migrations/0003_bi_views.sql

@@ -1,7 +1,7 @@
--- 0003_bi_views.sql: the views Superset reads through Trino (schema `public`), plus
--- fm.v_site_baseline_status. Owned by fuel_owner, so trino_ro can read them through the existing
--- default privileges; they run with the owner's rights, so Trino never reads `fm` (it lists fm's
--- table names, as it lists every schema's, but any query on them is refused).
+-- 0003_bi_views.sql: the views Superset reads (schema `public`), plus
+-- fm.v_site_baseline_status. Owned by fuel_owner, so fuel_ro can read them through the existing
+-- default privileges; they run with the owner's rights, so fuel_ro never reads `fm` (the catalog
+-- shows fm's table names, as it shows every schema's, but any query on them is refused).
 -- DRAFT, not applied. Applied after 0002 by a loader acting as fuel_owner (README in this folder).
 -- Design: fuel-monitoring .context/plans/2026-10-24-fuel-db-baseline-dashboard.md, §5.2 and §6.
 BEGIN;
@@ -97,7 +97,7 @@ LEFT JOIN pp USING (site_uid) LEFT JOIN fm.v_site_baseline_status bs USING (site
 LEFT JOIN cal USING (site_uid) LEFT JOIN latest USING (site_uid);
 
 -- Every view below joins public.v_site for site_uid, site_code, site_name and site_label, so one
--- Site filter drives every dataset, and casts to Trino-safe types (varchar(n), integer,
+-- Site filter drives every dataset, and casts to plain types (varchar(n), integer,
 -- numeric(p,s), date, timestamp(0), boolean). Live = asserted, reviewed or disputed.
 
 -- S2, R3: one row per site and measure; the rows stay when a value is not established.