perf(scheduler): harden jobs for scalable execution

server/migrations/20260520141000_add_scheduler_safe_indexes.down.sql

@@ -0,0 +1,6 @@
+DROP INDEX IF EXISTS idx_tenant_plan_active_window;
+DROP INDEX IF EXISTS idx_brands_monitoring_daily_candidate;
+DROP INDEX IF EXISTS idx_platform_accounts_monitoring_client_platform;
+DROP INDEX IF EXISTS idx_desktop_clients_active_plan_candidate;
+DROP INDEX IF EXISTS idx_schedule_task_due_dispatch;
+DROP INDEX IF EXISTS idx_schedule_task_missing_next_run;

server/migrations/20260520141000_add_scheduler_safe_indexes.up.sql

@@ -0,0 +1,30 @@
+CREATE INDEX IF NOT EXISTS idx_schedule_task_missing_next_run
+    ON schedule_tasks (created_at, id)
+    WHERE deleted_at IS NULL
+      AND status = 'enabled'
+      AND next_run_at IS NULL;
+
+CREATE INDEX IF NOT EXISTS idx_schedule_task_due_dispatch
+    ON schedule_tasks (next_run_at, id)
+    WHERE deleted_at IS NULL
+      AND status = 'enabled'
+      AND next_run_at IS NOT NULL;
+
+CREATE INDEX IF NOT EXISTS idx_desktop_clients_active_plan_candidate
+    ON desktop_clients (tenant_id, workspace_id, created_at, id)
+    INCLUDE (last_seen_at)
+    WHERE revoked_at IS NULL;
+
+CREATE INDEX IF NOT EXISTS idx_platform_accounts_monitoring_client_platform
+    ON platform_accounts (tenant_id, workspace_id, client_id, platform_id)
+    WHERE deleted_at IS NULL
+      AND client_id IS NOT NULL;
+
+CREATE INDEX IF NOT EXISTS idx_brands_monitoring_daily_candidate
+    ON brands (tenant_id, created_at, id)
+    WHERE deleted_at IS NULL;
+
+CREATE INDEX IF NOT EXISTS idx_tenant_plan_active_window
+    ON tenant_plan_subscriptions (tenant_id, start_at, end_at, plan_id)
+    WHERE status = 'active'
+      AND deleted_at IS NULL;