fix: add statement-breakpoint to migration 0025 and regenerate upgrade SQL

Better-SQLite3 requires --> statement-breakpoint between each statement
in a migration file; without it all statements are passed as a single
string to Database.prepare() which throws RangeError on multi-statement input.

src/server/db/generated/mysql.upgrade.sql

@@ -1 +1 @@
-ALTER TABLE `sites` ADD COLUMN `post_refresh_probe_latency_threshold_ms` INT DEFAULT 0;
+-- no schema changes detected for mysql

src/server/db/generated/postgres.upgrade.sql

@@ -1 +1 @@
-ALTER TABLE "sites" ADD COLUMN "post_refresh_probe_latency_threshold_ms" INTEGER DEFAULT 0;
+-- no schema changes detected for postgres