fix: add new migration to ensure agent schedule columns exist

Previous migration (20260426130000) may be recorded as failed in
_prisma_migrations after a db push conflict. This new migration with
a different timestamp will be seen as pending and applied with
idempotent SQL that handles both cases.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

memento-note/prisma/migrations/20260426140000_ensure_agent_schedule_columns/migration.sql

@@ -0,0 +1,16 @@
+-- Ensure agent schedule columns exist (idempotent)
+-- Handles both: fresh DB (columns missing) and DB where columns were added by db push
+DO $$ BEGIN
+  ALTER TABLE "Agent" ADD COLUMN "scheduledTime" TEXT DEFAULT '08:00';
+EXCEPTION WHEN duplicate_column THEN NULL;
+END $$;
+
+DO $$ BEGIN
+  ALTER TABLE "Agent" ADD COLUMN "scheduledDay" INTEGER;
+EXCEPTION WHEN duplicate_column THEN NULL;
+END $$;
+
+DO $$ BEGIN
+  ALTER TABLE "Agent" ADD COLUMN "timezone" TEXT;
+EXCEPTION WHEN duplicate_column THEN NULL;
+END $$;