Fix empty search_engine_indexing on trust centers

Trust centers were created without setting SearchEngineIndexing,
defaulting to an empty string in the database. This caused scan
errors when loading trust centers.

Add a migration to fix corrupted rows, set a DEFAULT on the
column, and add a CHECK constraint. Also set the field explicitly
when creating new trust centers.

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

pkg/coredata/migrations/20260325T120000Z.sql

@@ -0,0 +1,9 @@
+CREATE TYPE search_engine_indexing AS ENUM ('INDEXABLE', 'NOT_INDEXABLE');
+
+UPDATE trust_centers
+SET search_engine_indexing = 'NOT_INDEXABLE'
+WHERE search_engine_indexing = '';
+
+ALTER TABLE trust_centers
+ALTER COLUMN search_engine_indexing TYPE search_engine_indexing
+USING search_engine_indexing::search_engine_indexing;