chore: lock the plugin boundary and remove 2.9.0 leftovers

drizzle/sqlite/0045_public_menace.sql

@@ -1,3 +1,4 @@
-DROP TABLE `dashboard_service_links`;--> statement-breakpoint
-DROP TABLE `homepage_items`;--> statement-breakpoint
-DROP TABLE `homepage_layouts`;
+-- dashboard_service_links, homepage_items and homepage_layouts moved to the
+-- homepage plugin, which adopts them by rename at activation. Dropping them
+-- here would delete every row before the plugin's migration runs.
+SELECT 1;