perf(db): add revision and module query indexes

Индексы для diff/list префиксов и сортировки модулей; covering index для pagination.

Co-authored-by: Cursor <cursoragent@cursor.com>

migrations/postgres/000014_query_indexes.down.sql

@@ -0,0 +1,6 @@
+DROP INDEX IF EXISTS idx_rev_mat_prefix_uniq;
+DROP INDEX IF EXISTS idx_rev_mat_prefix_rev_cover;
+CREATE INDEX IF NOT EXISTS idx_rev_mat_prefix_rev_id
+    ON revision_materialized_prefix (revision_id, id);
+DROP INDEX IF EXISTS idx_module_tenant_active_sort;
+DROP INDEX IF EXISTS idx_rev_mat_prefix_rev_prefix;