[PR 1] Add experimental Custom Roles foundation (#7847)

migrations/postgresql/2026-10-10-120000_add_custom_role_permissions/up.sql

@@ -0,0 +1,13 @@
+-- The granular permissions of the Custom member role. They only take effect on a Custom membership
+-- (atype 4) while EXPERIMENTAL_CUSTOM_ROLES is enabled, and every existing membership starts without any.
+-- A single statement, so an interrupted upgrade cannot leave only some of the columns behind.
+ALTER TABLE users_organizations
+    ADD COLUMN manage_users BOOLEAN NOT NULL DEFAULT FALSE,
+    ADD COLUMN manage_groups BOOLEAN NOT NULL DEFAULT FALSE,
+    ADD COLUMN manage_policies BOOLEAN NOT NULL DEFAULT FALSE,
+    ADD COLUMN create_new_collections BOOLEAN NOT NULL DEFAULT FALSE,
+    ADD COLUMN edit_any_collection BOOLEAN NOT NULL DEFAULT FALSE,
+    ADD COLUMN delete_any_collection BOOLEAN NOT NULL DEFAULT FALSE,
+    ADD COLUMN access_event_logs BOOLEAN NOT NULL DEFAULT FALSE,
+    ADD COLUMN access_import_export BOOLEAN NOT NULL DEFAULT FALSE,
+    ADD COLUMN access_reports BOOLEAN NOT NULL DEFAULT FALSE;