Retire the Superset reader setup and the ATOMA dashboard (PD-13)

ATOMA's users use the Petrolyst app; Superset keeps admins, editors and the
app's embedded dashboards. Removed: the "ATOMA Reader" role and its rules
(petrolyst_reader.py, ReaderAccessMixin, reader.css, the head template, the
SQL-hiding patch), the atoma-reader mapping (it now maps to nothing in
Superset), the iframe allowance for the Map tab, and the "atoma" dashboard
with its Fleet/Map tab, D0 and dashboard.css. The bundle holds atoma-overview
and atoma-site only (byte-identical to before); the guest role keeps the
reader's 12 permissions in roles/atoma_guest.py. Brand files now name
petrolyst-web. SPEC marks the retired parts as history.

Checks (local): bundle checks pass; image rebuilt and healthy; import with
column drift 0 and unchanged embedding ids; the production config loads with
OAuth, embedding off, no reader hook; admin sees atoma-site with its tabs and
filter column; the app's browser tests pass 10/10. shellcheck not run (not
installed). Not deployed.

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

keycloak/petrolyst-partial-import.json

@@ -49,7 +49,7 @@
         { "name": "superset-admin", "description": "Superset Admin at atoma.petrolyst.com" },
         { "name": "superset-editor", "description": "Superset Alpha: build charts and dashboards" },
         { "name": "superset-viewer", "description": "Superset Gamma: view dashboards shared with the role" },
-        { "name": "atoma-reader", "description": "Superset ATOMA Reader: read the ATOMA dashboard only" },
+        { "name": "atoma-reader", "description": "ATOMA's users: the Petrolyst app (no role in Superset)" },
         { "name": "traefik-admin", "description": "Traefik dashboard at traefik.petrolyst.com" }
       ]
     }